What PSI to get an AR-15 action to cycle?

[Fx51LP308]

Possible that the chamber is fubar and causing extra drag when extracting the spent cartridge. Does the bcg jam in the barrel without a cartridge? There is no reason that a snap cap should cause the action to jam.

My 22 Grendel was sluggish for the first few mags, but eventually smoothed out. My hypothesis is that a minor chamber imperfection was dragging on the spent cartridges, but polished out with use. Possible that the bolt lugs needed to wear in too.

Can you manually lock back the bcg? Does it lock on the bolt or the nose of the carrier?

I'll be checking the upper very carefully for burs in the BCG track, etc. I will also give it a bit more oil. It might be a little light on that. No, the BCG never jammed when the upper was empty and without a mag. I'll check that again once I clear it this time. I get the feeling that the ejection is handled better than the feeding. But we'll see. Right now, I have to clear the jam that keeps me from operating the charging handle. Then we'll figure things out.

No, I cannot manually lock the BCG in the open action position. But that I think may be due to a week bolt release button. Perhaps, a bad spring. I'll replace it and see. And, of course, it won't lock when cycling and the mag goes empty.

 

[hlee]

Sanity check, once you get the jam cleared. Can you use the charging handle to pull the bolt far enough back to clear the bolt catch? In other words, does the rifle have the ability to lock open. Getting a 5.56/223 ar15 to run shouldn’t be this difficult.

 

[Fx51LP308]

Sanity check, once you get the jam cleared. Can you use the charging handle to pull the bolt far enough back to clear the bolt catch? In other words, does the rifle have the ability to lock open. Getting a 5.56/223 ar15 to run shouldn’t be this difficult.

No, the bolt catch does not lock the bolt back. It has always been an issue. I may have to replace the spring on it. Or, if that won't make a difference, then I guess we're talking replacement of the entire upper or the BCG, depending on what's cause the bolt catch not to work.

 

[TheBigCountry]

Been following this thread, and my one question is, is there away you can get it to a competent GS?

 

[Fx51LP308]

Been following this thread, and my one question is, is there away you can get it to a competent GS?

I could, and I might if I find things way too frustrating. But one of the objectives of this is for me to learn how to do it, so I can do it again, and again. I still have some fight left in me.

 

[hlee]

If you cannot manually drag the bolt carrier back far enough for the bolt catch to engage on the front of the bolt, then you have a fitment issue that needs to be resolved. And, this could appear to be under gassing and short stroking because the bcg is not moving as

Maybe you also have a bolt catch issue, but let’s start with the bcg. Pull the action open with the charging handle, then look in to the ejection port. Note the position of the bolt face relative to the bolt catch. Manually actuate the bolt catch while the bcg is fully to the rear. If it does not come up to block the bolt face from moving forward, where is the interference? If it does block the bolt face, or the bolt is far enough back that it could, then you have eliminated this potential issue from the list.

Now, let’s check the bolt catch. Pull the upper from the lower. Set the upper aside. Grab a magazine and insert it into the lower. Note that the magazine follower interacts with a tab on the bolt catch to move it into the engaged position. The bolt catch spring keeps the bolt catch in the down position. A weak spring would only serve to allow the bolt catch to engage when it should not. If the magazine follower moves the bolt catch up into the engages position, then it is working properly. If it does not, where is the interference?

Oh, and go buy a damned car already.

 

[Fx51LP308]

If you cannot manually drag the bolt carrier back far enough for the bolt catch to engage on the front of the bolt, then you have a fitment issue that needs to be resolved. And, this could appear to be under gassing and short stroking because the bcg is not moving as

When not "jammed," I can drag the BCG back completely to where the bolt catch should engage. But, for whatever reason, it won't. It could be a weak/incorrect spring. There's not a lot of travel in the bolt catch. I pull the charging handle all the way back, and then I try to release it slowly to catch it manually so that it will engage, but it never does. I feel it "click" but the BCG just goes right by it. It could also be a bad bolt catch tab or some other issue requiring its replacement. Better to replace a bad bolt catch than an entire upper.

Maybe you also have a bolt catch issue, but let’s start with the bcg. Pull the action open with the charging handle, then look in to the ejection port. Note the position of the bolt face relative to the bolt catch. Manually actuate the bolt catch while the bcg is fully to the rear. If it does not come up to block the bolt face from moving forward, where is the interference? If it does block the bolt face, or the bolt is far enough back that it could, then you have eliminated this potential issue from the list.

I haven't eliminated that just yet, but I will, shortly, once I clear this latest jam. Currently, I cannot pull back the charging handle at all. There is one snap cap "in battery" with no mag loaded, but the charging handle will not budge. I'll get back to you once that's cleared.

Now, let’s check the bolt catch. Pull the upper from the lower. Set the upper aside. Grab a magazine and insert it into the lower. Note that the magazine follower interacts with a tab on the bolt catch to move it into the engaged position. The bolt catch spring keeps the bolt catch in the down position. A weak spring would only serve to allow the bolt catch to engage when it should not. If the magazine follower moves the bolt catch up into the engages position, then it is working properly. If it does not, where is the interference?

I will check that out.

Oh, and go buy a damned car already.

Only if you're willing to pay for it.... and the fuel.... and the insurance, etc. etc. etc. Right now, I'm still ahead of the game, expensewise, with my current level of vehicle rentals, Uber/Lyft rides, etc. 2022 will tell the tale, as it would be my first full year of JTAC visits (at least once a month) where I have to rent each time. We'll see.

 

[mtrmn]

When not "jammed," I can drag the BCG back completely to where the bolt catch should engage. But, for whatever reason, it won't. It could be a weak/incorrect spring. There's not a lot of travel in the bolt catch. I pull the charging handle all the way back, and then I try to release it slowly to catch it manually so that it will engage, but it never does. I feel it "click" but the BCG just goes right by it. It could also be a bad bolt catch tab or some other issue requiring its replacement. Better to replace a bad bolt catch than an entire upper.



I haven't eliminated that just yet, but I will, shortly, once I clear this latest jam. Currently, I cannot pull back the charging handle at all. There is one snap cap "in battery" with no mag loaded, but the charging handle will not budge. I'll get back to you once that's cleared.



I will check that out.



Only if you're willing to pay for it.... and the fuel.... and the insurance, etc. etc. etc. Right now, I'm still ahead of the game, expensewise, with my current level of vehicle rentals, Uber/Lyft rides, etc. 2022 will tell the tale, as it would be my first full year of JTAC visits (at least once a month) where I have to rent each time. We'll see.

Sounds to me like the bolt catch is trying to catch the front of the bolt CARRIER, not the bolt itself.

 

[Blutroop]

Edit

 

[mtrmn]

You need to understand also that the MAGAZINE FOLLOWER IN AN EMPTY MAGAZINE is what causes the bolt catch to engage, NOT the spring in the bolt catch assembly.
Also, if the bolt catch will not engage the front surface of the bolt, then that likely means the bolt carrier group is not traveling far enough rearward due to an improper buffer/spring/tube combination.
The gun will never properly function until this problem is dealt with.

 

[Fx51LP308]

You need to understand also that the MAGAZINE FOLLOWER IN AN EMPTY MAGAZINE is what causes the bolt catch to engage, NOT the spring in the bolt catch assembly.
Also, if the bolt catch will not engage the front surface of the bolt, then that likely means the bolt carrier group is not traveling far enough rearward due to an improper buffer/spring/tube combination.
The gun will never properly function until this problem is dealt with.

Thank you. I'll confirm this.

 

[BillyNg]

On a more serious note, have any of you fellers priced car insurance in the Tampa Bay area?
It's fucking outrageous!!

Arnold, buy yourself a reliable scooter and strap your toys on your back to make the trek to JTAC.

Or get this one and you have a passenger seat...

View attachment 7693336


It'll cost a lot less than 6 months worth of insurance.

I doubt it comes close to what I've paid. $4200/year for liability only on a used 4-cyclinder when I was 18 and living one town away from Newark, NJ. Eventually moved to Brooklyn and went motorcycle-only. Full coverage was over $3K/year - on a bike!! Then got pregnant and bought a 10 year old Subaru Forester for $7K. In Brooklyn, they charged me $3200/year for full coverage on that car, thankfully, I only lived there for another 6 months.

Now I live in Westchester county NY, I'm paying a little under $6K/year for 3 cars. A 7 year old Camaro, a 9 year old M3, and a 2 year old Subaru Ascent. We haven't had any claims in the 15 years we've lived here and neither of us has points on our license.

 

[Mike Casselton]

I doubt it comes close to what I've paid. $4200/year for liability only on a used 4-cyclinder when I was 18 and living one town away from Newark, NJ. Eventually moved to Brooklyn and went motorcycle-only. Full coverage was over $3K/year - on a bike!! Then got pregnant and bought a 10 year old Subaru Forester for $7K. In Brooklyn, they charged me $3200/year for full coverage on that car, thankfully, I only lived there for another 6 months.

Now I live in Westchester county NY, I'm paying a little under $6K/year for 3 cars. A 7 year old Camaro, a 9 year old M3, and a 2 year old Subaru Ascent. We haven't had any claims in the 15 years we've lived here and neither of us has points on our license.

Our insurance is so high because of New Yorkers...

 

[S197]

It sounds like you have a lot going on with this rifle.

if it is a snap cap stuck. Get a wooden dowel and rubber mallet and a few good wacks on the CH.

After that is clear, let’s talk about your rifle.
Did you build it or is it a factory build?
did you check the headspace?
Who is the barrel built by?
Is your barrel stamped.223 rem 223 wyld or 556.
what ammo where you using?
Did you get Jams like this with live ammo? If so what ammo jammed it.. 223 or 556?
Have you inspected the gas rings on your bolt? How dose the rings, cam pin and the bolt look? Any pinning (impact marks)?

 

[eastexsteve]

No, I cannot manually lock the BCG in the open action position. But that I think may be due to a week bolt release button. Perhaps, a bad spring. I'll replace it and see. And, of course, it won't lock when cycling and the mag goes empty.

Not to beat a dead horse here, but you should be able to manually lock the bolt back with an empty mag in the lower. If it won't lock back when it empties a mag after firing, that's another issue. (I'm assuming it's a good mag.) It doesn't take much of a bolt release spring as long as it it holding the bolt release in the locked position. If the mag is good, the bolt release is locked, and you still can't manually lock it back on an empty mag, then you have a bolt catch problem, or some kind of weird fitment issue with the bolt/BCG.

When you load one round in the mag and fire it, did it ever eject the empty round? If so, where did it pitch it on the ground?

As someone above said, it's just not that hard to get a 5.56 gun to run right.

 

[Fx51LP308]

It sounds like you have a lot going on with this rifle.

if it is a snap cap stuck. Get a wooden dowel and rubber mallet and a few good wacks on the CH.

I don't think the current issue is because the snap cap is stuck. I think the problem is the BCG binding. It's not letting me pull the charging handle back.

After that is clear, let’s talk about your rifle.
Did you build it or is it a factory build?

I built it from scratch. It was my 1st build, and that was the point. For me to learn how to build an AR and to deal with all the problems of doing so. And I am.

did you check the headspace?
Who is the barrel built by?
Is your barrel stamped.223 rem 223 wyld or 556.

It's a 5.56 barrel and so marked. I forget the barrel manufacturer but it was one offered on the Primary Arms website. Previously, when I was diagnosing the gas block issues, the weapon would fire properly if I manually cycled it. I don't think it's he barrel.

what ammo where you using?

Federal XM855 Green Tip (62gr).

Did you get Jams like this with live ammo? If so what ammo jammed it.. 223 or 556?
Have you inspected the gas rings on your bolt? How dose the rings, cam pin and the bolt look? Any pinning (impact marks)?

I'll check that but, again, the weapon did fire properly at one point when I operated the charging handle manually.

Right now, I think my primary focus should be on the upper and the BCG binding. I'll get back to you, once I've checked that.

 

[Fx51LP308]

Not to beat a dead horse here, but you should be able to manually lock the bolt back with an empty mag in the lower.

I believe I've tested this already (i.e. with an empty mag) and it failed, but I will re-confirm that test once I clear this latest jam.

If it won't lock back when it empties a mag after firing, that's another issue. (I'm assuming it's a good mag.)

Yes, they are MAGPUL PMAG-30's Gen 3.

It doesn't take much of a bolt release spring as long as it it holding the bolt release in the locked position. If the mag is good, the bolt release is locked, and you still can't manually lock it back on an empty mag, then you have a bolt catch problem, or some kind of weird fitment issue with the bolt/BCG.

I think it is a "bolt catch" problem. But it's not the only problem. I think there's some BCG binding going on at this point.

When you load one round in the mag and fire it, did it ever eject the empty round? If so, where did it pitch it on the ground?

Yes, the round does eject now when fired. The gas problems I was having earlier I now beleive are resolved. It goes straight out.

As someone above said, it's just not that hard to get a 5.56 gun to run right.

I would agree. But since it is my "1st build' on my own (with a little "cyber advice"), there are bound to be problems to resolve.

I will not give up. I will make it right.

 

[TonyTheTiger]

I would agree. But since it is my "1st build' on my own (with a little "cyber advice"), there are bound to be problems to resolve.

I will not give up. I will make it right.

Not really. Small frame AR's are pretty plug and play. I'm not trying to be a dickhead, but you must have some very incompatible parts combos going on.

 

[Fx51LP308]

Not really. Small frame AR's are pretty plug and play. I'm not trying to be a dickhead, but you must have some very incompatible parts combos going on.

If that be the case, then I'll correct that with the right parts. Right now, I'm using an Anderson Lower/upper combo, which came with BCG, charging handle etc. etc. How often is that combo "incompatible?"

 

[TonyTheTiger]

If that be the case, then I'll correct that with the right parts. Right now, I'm using an Anderson Lower/upper combo, which came with BCG, charging handle etc. etc. How often is that combo "incompatible?"

Without reading the whole thread again, I would guess those parts are fine. I'm sure someone has already mentioned gas leaks and block alignment, the gas rings should be fine on a new BCG, gas key screws shouldn't be broken yet. Are you sure you have all the right buffer components? Carbine buffer tube/carbine spring/carbine buffer etc. If one of those parts is rifle length you'll have some weird issues. Same story if you have a rifle system with one carbine part mixed in. And check headspace just to rule it out.

 

[Fx51LP308]

Without reading the whole thread again, I would guess those parts are fine. I'm sure someone has already mentioned gas leaks and block alignment, the gas rings should be fine on a new BCG, gas key screws shouldn't be broken yet.

I have double checked all the gas components and, after dimpling my barrel correctly, I think they are delivery sufficient gas I will re-check the key again but I would agree that it's not the culprit.

Are you sure you have all the right buffer components? Carbine buffer tube/carbine spring/carbine buffer etc

Absolutely. Carbine buffer, carbine spring (not rifle length).

And check headspace just to rule it out.

OK

 

[chevy_man]

If that be the case, then I'll correct that with the right parts. Right now, I'm using an Anderson Lower/upper combo, which came with BCG, charging handle etc. etc. How often is that combo "incompatible?"

Do you have friends with ARs?

Easiest way to troubleshoot is swap 1 part at a time with a good running one.

I've seen carbine buffers that wouldn't actually fit in a carbine buffer tube. Needed to shave .1" off to get the BCG back far enough to catch on the hold open.

I'm wondering if something is up with your cam pin or track that's causing the BCG to stick.

Anderson stuff is usually fine, but you won't find any fan boys of it. Don't stress on the maker, just start measuring stuff.


I guess I must live in utopia, I'm paying $1k/year for insurance on 4 trucks. I have a Yukon that is only for going to the range and matches. They're all paid for, because I'm not scared to drive something without a warranty.
You could buy a $1500 car and use it for range trips, liability insurance only, and be cheaper than renting all the time. I can't imagine not being at the range at least 1 time a week, I'm usually there 3-5 times every weekend.

 

[Fx51LP308]

Do you have friends with ARs?

Easiest way to troubleshoot is swap 1 part at a time with a good running one.

I actually have all the parts needed for a 2nd build. I was hoping not to use them on the 1st, but I will if need be to check things out.

I've seen carbine buffers that wouldn't actually fit in a carbine buffer tube. Needed to shave .1" off to get the BCG back far enough to catch on the hold open.

I'm wondering if something is up with your cam pin or track that's causing the BCG to stick.

I'll check that out as well. Thanks!

Anderson stuff is usually fine, but you won't find any fan boys of it. Don't stress on the maker, just start measuring stuff.

Gotcha.

I guess I must live in utopia, I'm paying $1k/year for insurance on 4 trucks. I have a Yukon that is only for going to the range and matches. They're all paid for, because I'm not scared to drive something without a warranty.
You could buy a $1500 car and use it for range trips, liability insurance only, and be cheaper than renting all the time. I can't imagine not being at the range at least 1 time a week, I'm usually there 3-5 times every weekend.

We'll see. I committed to another full year doing it this way and then I'll make the call. I'd have to lease a car if I go back (about $300.00/mo. plus fuel, insurance and maintenance) but we'll see.

 

[wyld3man]

Maybe check this too.

The reason you dont mount the gas block flush with the barrel shoulder

This comes up very often. Guys take there new gas block and butt it up to the shoulder of the barrel. This is incorrect unless stated differently in your gas block instructions. The reason is the proper gas block location allows for an A2 handguard endcap to be placed between the gas block and ba...

forum.308ar.com

People actually still use A2 hand guards? Those things are just about antiques by now.

Let me give you some car advice. When the time comes I would not lease a car, just buy it. Then once it’s paid off you can either enjoy no car payment or trade it in and have a decent down payment. It’s like renting a house vs. buying one, each month you are pissing away your money.

If you still have the snap cap jammed the most common way to clear it is: 1. Grab the hand guard with non dominant hand 2. Point the barrel skywards 3. grab the charging handle with dominant hand 3. At the same time slam the buttstock into some hard ground/ surface while at the same time pulling the charging handle to the rear.

 

[mtrmn]

People actually still use A2 hand guards? Those things are just about antiques by now.

Let me give you some car advice. When the time comes I would not lease a car, just buy it. Then once it’s paid off you can either enjoy no car payment or trade it in and have a decent down payment. It’s like renting a house vs. buying one, each month you are pissing away your money.

If you still have the snap cap jammed the most common way to clear it is: 1. Grab the hand guard with non dominant hand 2. Point the barrel skywards 3. grab the charging handle with dominant hand 3. At the same time slam the buttstock into some hard ground/ surface while at the same time pulling the charging handle to the rear.

And scope the stock all the way in to the shortest position first.

 

[hlee]

light(ish) raps on the charging handle with a non-marring mallet can also work...

 

[redneckbmxer24]

I just read this whole thread. Jesus Christ man, you should just go buy a quality AR and be done with that nightmare hodgepodge bag of parts.

Also a car.

 

[Fx51LP308]

I just read this whole thread. Jesus Christ man, you should just go buy a quality AR and be done with that nightmare hodgepodge bag of parts.

Also a car.

That would be the easiest thing to do, wouldn't it? But "easy" is not the point. The point is for me to learn how to do it. And I'm learning a lot. Making mistakes? Absolutely. But that's the best way to learn something if you can afford to do so (I guess you can't afford mistakes when you're out in a battle in the field). But, since I'm not...

And I have another year to go on my economic test. If in a year, I find it more expensive to rent cars/do Uber/Lyft, then I'll look at leasing a car. FOr now, I'm doing OK.

 

[JohnCarter17]

I don't know if anyone posted the world's easiest way to align the gas block yet, but here it is.
This is for barrel not in gun.

1) get a toothpick, or a thin piece of pasta.
2) with the gas block off, whittle toothpick down if needed. Make sure it easily fits into the gas port.
3) snap it off so it is entirely in the barrel
4) put on the gas block, adjust with shim from shoulder (lots of GBs need this done) and partially tighten.
5) look through muzzle end with chamber end facing a light source, barrel is gas side up.
6) find the toothpick. 180 the barrel so the toothpick drops (mostly/partially) into the GB,
7) do this several times to confirm easy motion of the toothpick/pasta.
8) its aligned. Tighten up GB, use blue loctite, etc.
9) break obstructor with cleaning rod and remove from barrel.

A compressor is not needed. Block chamber with a finger, another on end of gas tube and blow down the freaking barrel.
You can confirm function that way.

Also make sure the gas key is easily mating with the gas tube to confirm alignment.
With upper off gun and upside down, move BCG back and forth make sure it is smooth with no resistance when mating to gas tube.

And take the extractor off bolt and remove the worthless fucking o-ring. Not needed.

 

[Fx51LP308]

I don't know if anyone posted the world's easiest way to align the gas block yet, but here it is.
This is for barrel not in gun.

1) get a toothpick, or a thin piece of pasta.
2) with the gas block off, whittle toothpick down if needed. Make sure it easily fits into the gas port.
3) snap it off so it is entirely in the barrel
4) put on the gas block, adjust with shim from shoulder (lots of GBs need this done) and partially tighten.
5) look through muzzle end with chamber end facing a light source, barrel is gas side up.
6) find the toothpick. 180 the barrel so the toothpick drops (mostly/partially) into the GB,
7) do this several times to confirm easy motion of the toothpick/pasta.
8) its aligned. Tighten up GB, use blue loctite, etc.
9) break obstructor with cleaning rod and remove from barrel.

A compressor is not needed. Block chamber with a finger, another on end of gas tube and blow down the freaking barrel.
You can confirm function that way.

Also make sure the gas key is easily mating with the gas tube to confirm alignment.
With upper off gun and upside down, move BCG back and forth make sure it is smooth with no resistance when mating to gas tube.

And take the extractor off bolt and remove the worthless fucking o-ring. Not needed.

Thanks much. I actually saw a video on the "pasta" method of alignment. But the gas block issues I believe are now resolved. I just have to get the upper/BCG to work now.

 

[JohnCarter17]

I actually have all the parts needed for a 2nd build. I was hoping not to use them on the 1st, but I will if need be to check things out.

No. That isn't what he meant.

With ARS we are absolutely blessed that over 2 dozen things can be responsible for failures to function.

Its about using a functional AR as a comparison with your parts.
As you swap parts, you can determine what is the issue if yours starts working normally.

Find someone with a working AR and ask to help you diagnose.

Swap BCGs. Test fire. What happens with his in yours and vice versa?
If your BCG in his rifle functions fine, its not the BCG fit/finish. If your AR starts working fine with his BCG it is the BCG.

Swap the entire upper. That allows you to see if its related to the buffer and spring, assuming gas system length is compatible.
Next swap the buffer. Then the buffer spring.


Also do this. With your upper off and BCG out manually chamber a round. Elevate to muzzle vertical.
Does the round fall out easily and is the brass not marred?

That will (possibly) eliminate a pathetic reaming job on the barrel as being an issue.

 

[Fx51LP308]

No. That isn't what he meant.

With ARS we are absolutely blessed that over 2 dozen things can be responsible for failures to function.

Its about using a functional AR as a comparison with your parts.
As you swap parts, you can determine what is the issue if yours starts working normally.

Find someone with a working AR and ask to help you diagnose.

Ah, Gotcha. I wish I could find such a person. All the help I've gotten so far has been "cyber help." I don't think I live near anyone who could loan me one of their ARs for diagnostic purposes. If it came to that, then I'd probably be better off buying a fully functioning AR (as mentioned above), test that, and then fix the one I built. Of course, by then, y'all be on my a$$ for not saving that money up to buy/lease a new car!

Also do this. With your upper off and BCG out manually chamber a round. Elevate to muzzle vertical.
Does the round fall out easily and is the brass not marred?

That will (possibly) eliminate a pathetic reaming job on the barrel as being an issue.

That, I can, and will definitely do. Thanks!. I'll also do the upper/BCG tests you mentioned.

 

[Fx51LP308]

Update: 2nd round of diagnosis completed. I note the following:

1) The above "elevated barrel" test was successful with a live round, but only a live round. It failed with one of my snap caps (had to self extract with needle nose pliers) as well as an empty shell. Neither of those had the same weight as a full live round (obviously). In fact, because of that, I believe these snap caps I have (plastic) are worthless because they don't simulate the full weight of a live 5.56 62 gr round.

2) The current jam cleared once I pulled the charging handle with some extra force, and the plastic snap cap ejected. But I'm thinking there may be some damage to the upper now. See this picture and see the aluminum sheer on the lower inside of the upper tract. This pic, of course, is with the BCG and charging handle removed. Note the gas tube is in place and is covered by the key when in full battery.

3) I did some tests with the BCG. I maunally loaded both my snap cap and the empty shell into the barelhead and attempted to close the BCG manually and get it into battery. It would not lock all the way into battery when I tried this.

The following is the BCG in full "unlocked" position (ie. bolt head fully extended).

When I pushed the BCG in after hand loading any/all items, it would only go halfway into battery. Like so: (Now it's on its side, now).

After giving everything a light coat of oil and replacing the parts, I noticed that when I pushed the BCG in with nothing loaded, it went into full battery, as follows (this pic is with BCG and charging handle properly installed into the upper):

I then re-assembled the upper to the lower and tested the charging handle, etc, etc. with no rounds. It also went into full battery (I could observe the BCG through the ejection port). Thinking that the problems may be with the snap cap and empty shell, I then went ahead and loaded one live round from the mag. I pulled the charging handle, and it responded correctly, going into full battery. I then removed the mag, pulled the charging handle, and the loaded live round did eject properly.

Conclusions:

1) Maybe it did need a small coat of oil.
2) I need to buy new snap caps that actually have the full weight of a live 62gr round.
3) If I still have issues after the next round of test firing, then I'll have to look at the buffer and spring next, or replacing the entire upper/BCG asssembly.

More to follow. Thanks.

 

[TonyTheTiger]

It takes some force to get the extractor over the rim if you load the round into the chamber first. You won't just be able to slowly push it into battery that way. Try putting the case on the bolt face, with the rim under the extractor, then guiding it into the chamber.

 

[Fx51LP308]

It takes some force to get the extractor over the rim if you load the round into the chamber first. You won't just be able to slowly push it into battery that way. Try putting the case on the bolt face, with the rim under the extractor, then guiding it into the chamber.

OK, thanks! I'll try that if I need to in my next diagnostic session.

 

[mtrmn]

During break-in you need a liberal coating of oil on and inside the BCG. I've found that a few drops periodically into the exhaust holes on the bolt carrier are the most important. Keep the gas rings wet until it wears in a bit.
Also-and you don't have to be at the range to do this-you need to address the problem with the bolt not locking open with an empty mag. When you manually pull the charging handle back until it stops the bolt locking lugs should be at least 1/8" behind the bolt catch. If not, you most likely have a mismatch of buffer/spring/buffer tube. If the bolt is not coming rearward far enough, the gun will never function as designed.

 

[Fx51LP308]

And, the ultimate update: SUCCESS!!!!

The action is now cycling completely! I was able to empty a whole PMAG-30 with no trouble. I guess it was just the "oil" thing inside the upper/BCG after I fixed the gas block issue. I even had @Mike Casselton bust a few rounds just to be sure. The scope is way off to the left per Mike, but I'll work on that shortly.

All that remains now is the bolt catch/release. Mike did suggest either a new spring, or maybe filing down the lever a little so it catches properly. I'll definitely take a look and post some pics for your review.

And, not only that, in re: the RPR, Mike got me out to 250 yards without any training. I hit the white target in between the cars. And icing on the cake, I got my first hit on the "pig" 1st shot. Of course, I missed all the others, but... That Armagedon "Schmedium" Squeeze bag is the "Schiznit!"

At any rate, a great morning had by myself with Mike and the guys. I look forward to the next one.

 

[wyld3man]

So, how about the Uber, still cheaper than a car? Bet that's an uncomfortable ride, just don't tell the driver you need to go to the bank first.

 

[Fx51LP308]

So, how about the Uber, still cheaper than a car? Bet that's an uncomfortable ride, just don't tell the driver you need to go to the bank first.

Right now, yes it is. I'm actually doing fewer Ubers due to Wally World delivering groceries for free ($99 annual fee for that service). I do Ubers (Lyft actually) now, only to go to my doctor or hair salon or things like that. And that's like once every 3 months.

What will offer that scenario some competition will be my monthly trips to JTAC Ranch. In that case, I'm renting a car for 1 day (or 2 max). You're looking at $130.00 for that (mid size car with damage waiver - I no longer have "insurance" since I don't own anything), including fuel etc. That's like $1500.00/yr. Right now, that might match the cost of leasing a really cheap car, but not include fuel, maintenance and/or insurance. And I've learned something from all these different rentals. One thing I loved about my old Toyota 4-Runner I had for 12 years is the ease of getting in/out of it. It was at the right height, etc. and a breeze to get in and out, with enough leg room, etc. (I have long legs). Not so with the "sub-compact" or "compact" models offered for rent, these days. They are a struggle to get in/out. And it's really hard to see above a certain level. I really miss those things about my old 4-Runner. So, I'll probably be renting "mid-size" henceforth. And, if the rental place is low on stock, I might actually get "upgraded" to an SUV or something (In this most recent case, I got upgraded to a Jeep Wrangler). And, should I go ahead and lease a vehicle, definitely an SUV or maybe even a "pickup." Would be the first pickup I ever acquired. Expensive to lease? Probably. So, all that goes into the calculation of which is cheaper.

 

[Fx51LP308]

On the "Bolt Catch/Release" issue -

Here are the pics I've taken. The first is of the Bolt Catch when not extended (i.e. charging handle not pulled back.

You can see that it doesn't fully cover the impression hole in the lower. I think that's what Mike was referring to when he said it's not properly oriented over the lower hole. Either that, or the spring is really weak.

Here's another view:

And another from the opposite side (sorry a bit out of focus):

If I open the lower and look at the inside, I see this:

And when I try to pull back the catch, I get this:

And, finally, from the other side:

I'll check this with my other lower and some additonal parts and then see what I may need to adjust. But if anything looks wrong, please advise.

Thanks & Regards,
Arnold.

 

[mtrmn]

I edited and brightened your pic, then made a pic of mine. Your bolt catch is not raising near far enough. Also not covering the hole where the spring and follower go is normal. If the spring is your problem, it would be much too strong (not "too weak") or too long for this application. Are you sure you used the right spring here? It takes very little effort to operate when it's right.
ETA: You should be able to insert an empty mag with the gun in this condition and the mag spring should push the bolt catch up. The spring installed in the gun has to be weak enough for the magazine spring to overcome it.

Yours:

Mine:

 

[Fx51LP308]

I edited and brightened your pic, then made a pic of mine. Your bolt catch is not raising near far enough. Also not covering the hole where the spring and follower go is normal. If the spring is your problem, it would be much too strong (not "too weak") or too long for this application. Are you sure you used the right spring here? It takes very little effort to operate when it's right.

That will be the first thing I check. It's quite possible that it's the wrong spring. I recall that when I started this build, I had opened the "Lower parts Kit" (the one where everything is in their little places on the kit) I had bought (that contained the bolt catch). It was the first thing I put on the lower. But I recall jostling the kit and everything coming out of it. I thought I had put it all back correctly into their slots, but I could be wrong. I will check it.

ETA: You should be able to insert an empty mag with the gun in this condition and the mag spring should push the bolt catch up. The spring installed in the gun has to be weak enough for the magazine spring to overcome it.

Yeah, that's definitely not happening. So, I'll be checking it. I now have parts for a 2nd build so I'll try it out on that lower and see how it "should" look, and then I'll fix this one.

Thanks much!

 

[Fx51LP308]

Another Update: I just did another test with an empty PMAG-30. This after the comments about it being the "follower" of an empty mag that causes the Bolt catch to engage. I put in an empty mag and pulled the charging handle. Lo and behold, it locked into place! But the slightest little jolt of the rifle would cause it to unlock and the handle/BCG to go back into battery. I can pull the charging handle back and it will lock into place, as long as I don't jolt the rifle. I can even drop the mag and will stay locked back. But not for long, as the slightest little bump will cause it to close. I guess the reason why it wouldn't lock back after firing the last round in the mag is that ejection jolt. When it is locked back, I can push the bolt catch release and it will close, normally.

So, that helps, a little in terms of diagnosis and repair. Either the spring is not enough to keep the bolt catch extended out when the handle is back, or something is off that it can't get a full catch... only a partial one.

Thoughts? Thanks!

 

[mtrmn]

Another Update: I just did another test with an empty PMAG-30. This after the comments about it being the "follower" of an empty mag that causes the Bolt catch to engage. I put in an empty mag and pulled the charging handle. Lo and behold, it locked into place! But the slightest little jolt of the rifle would cause it to unlock and the handle/BCG to go back into battery. I can pull the charging handle back and it will lock into place, as long as I don't jolt the rifle. I can even drop the mag and will stay locked back. But not for long, as the slightest little bump will cause it to close. I guess the reason why it wouldn't lock back after firing the last round in the mag is that ejection jolt. When it is locked back, I can push the bolt catch release and it will close, normally.

So, that helps, a little in terms of diagnosis and repair. Either the spring is not enough to keep the bolt catch extended out when the handle is back, or something is off that it can't get a full catch... only a partial one.

Thoughts? Thanks!

"Either the spring is not enough to keep the bolt catch extended out when the handle is back" The bolt catch spring installed in the gun does NOT hold the latch "extended"---that is the job of the MAGAZINE spring.

Thought we went over this. The bolt catch is not coming up high enough. This is probably due to the spring being TOO STRONG or TOO LONG. A 3rd problem could be some obstruction/foreign matter trapped behind the bolt catch spring or follower.
SEE ATTACHED PDF
In the PDF, you want your bolt catch to go high enough to achieve the BIG ANGLE-not the tiny angle. Something in the bolt catch SPRING ASSEMBLY is limiting the movement of the bolt catch and preventing this. Now go knock the roll pin out and remove the bolt catch, spring and follower to determine what the problem is.

 

[Fx51LP308]

"Either the spring is not enough to keep the bolt catch extended out when the handle is back" The bolt catch spring installed in the gun does NOT hold the latch "extended"---that is the job of the MAGAZINE spring.

Thought we went over this. The bolt catch is not coming up high enough. This is probably due to the spring being TOO STRONG or TOO LONG. A 3rd problem could be some obstruction/foreign matter trapped behind the bolt catch spring or follower.
SEE ATTACHED PDF
In the PDF, you want your bolt catch to go high enough to achieve the BIG ANGLE-not the tiny angle. Something in the bolt catch SPRING ASSEMBLY is limiting the movement of the bolt catch and preventing this. Now go knock the roll pin out and remove the bolt catch, spring and follower to determine what the problem is.

I've ordered a couple of Bolt catch kits (including spring, detent, and roll pin). At least I'll have parts I know are specifically designed for the bolt catch. Now, I just have to get the old parts out without damaging the lower. I'll use some penetrating oil to loosen up the installed roll pin and then punch it out.

 

[mtrmn]

I've ordered a couple of Bolt catch kits (including spring, detent, and roll pin). At least I'll have parts I know are specifically designed for the bolt catch. Now, I just have to get the old parts out without damaging the lower. I'll use some penetrating oil to loosen up the installed roll pin and then punch it out.

Thanks. Keep us updated....

 

[hlee]

Thought we went over this.

Yeah, I’ve given up. But, it’s like sitting on the front porch watching the neighbor kid learn to ride a bike. You just know he’s about to flip over the handle bars, so you keep watching.

All of the answers are in this thread- on the first page.

 

[Milf Dots]

That will be the first thing I check. It's quite possible that it's the wrong spring. I recall that when I started this build, I had opened the "Lower parts Kit" (the one where everything is in their little places on the kit) I had bought (that contained the bolt catch). It was the first thing I put on the lower. But I recall jostling the kit and everything coming out of it. I thought I had put it all back correctly into their slots, but I could be wrong. I will check it.

When you have another complete spring and pin kit to compare against, I'd completely disassemble the rifle to make sure you have every pin and spring located correctly and confirm no damage has occurred to anything that was in the wrong place. Better safe than sorry. Plus it'll give you practice building ARs, and a chance to clean and grease things that slide and oil things that pivot.

 

[Fx51LP308]

Thanks. Keep us updated....

Kit received today. Took less than 1hr to replace the Bolt Catch group.

These are some pics below of both the original group and the replacement group. The original is on the right. First the spring and detent.

You'll notice the spring on the right (original) is shorter and a little thicker, but it matches the fit of the detent/plunger on the right. The spring and detent/plunger on the left also match each other and the spring is softer. So, I conclude that the original spring and detent/plunger were the correct ones for the bolt catch group installed. But was the group itself correct?

Now, the view of the bolt catches, themselves. Original on the right.

You'll notice the big difference in design. I think this was the primary issue causing the catch not to lock. The spring didn't help either, but I think this was the real culprit.

I completely replaced the original parts with the replacements, all except the roll pin which fit back in properly.

The bolt catch works flawlessly, now. I tested it with some new snap caps that actually had the same weight as live rounds. They ejected properly and the last ejection resulted in the catch locking strongly. I dropped the empty mag and then gave the weapon a light bang, and it held. Only when I pressed the release did it close and go into battery. I will do a final test at JTAC this month at my next visit to confirm it will hold after firing/ejecting the last round in the mag.

Thanks to all for your help. The AR is fully functional now. Just have to keep it properly cleaned/lubed.

 

[JohnCarter17]

Who is the maker of the parts kit with the crappy mag release?