AR-10 Advice / recommendations

Goldbears93

Private
Minuteman
Apr 6, 2018
20
2
Hi there!!

About 2 years ago I dropped around 4K on a custom made 18” 308 AR-10. While the gun has an awesome barrel on it and is crazy accurate, I have had the worst time getting it function reliable. From failure to feeds to failure to ejects to bullets getting stuck in what seems to be a tight chamber, I can’t get it to cycle reliably. Not sure if this is due to right tolerances or what. But after taking to the gunsmith a couple times I am contemplating moving on.

with that said, I generally use this rifle mainly for hunting deer/hogs/ varmints anywhere from 100-600 yards and shoot steel out to 900 just for fun. I also run it with an omega full time. I mostly
Value accuracy and the gun not being too heavy or unwieldy given I carry it around a ranch all day and in an out of vehicles. (And obviously want it to function reliably

I have looked at the DD5V3, LT PredatOBR, Wilson Combat and the JP LRP-07.

As ashamed as I am to say it I also value the “coolness factor” a lot and want the rifle to look good. For the reason (I know it’s stupid) but I really don’t care for the JP hand guards and wish you could change them out cause I find them not great looking.

So basically looking for something in 6.5 or 308. Around 16 or 18” and is a good blend of accuracy and weight/maneuverability.

(price isn’t the biggest concern)

would love to hear yalls recommendations or what you have and how you like it!
 
SR25 for DI, HK for a piston. Both are accurate and reliable and the best examples of DI and piston AR respectively.

But since you said you have a tack driving .308 already, I'd consider the Mk20. I got mine for $3500 this summer. It's a bad bitch and will totally solve any semi .308 issues you have.

Then I'd go and figure out what's hindering the AR. I have a recipe for small frames but I don't know if it'll work for large ones. But the JP Ent. FMOS BCG is a key part for reliability in my assemblies. Probably something simple, maybe even cheap.

Handloading helps too but I know it's not for everyone.

I have several high end barrels in small frame AR's and zero issues suppressed or not and I don't own an adj. gas block. So I wouldn't really blame a tight chamber. I would look at your mags first if you haven't already. You oughta start a troubleshooting thread about it on here and follow up with what they say.
 
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Have you checked the standard issues of a large-frame AR? Feed ramps look good, checked extractor marks on brass, exchanged spring or buffer weights, adjusted gas if it's adjustable, confirmed gas block is properly positioned, everything is very well lubricated?

Does it feel soft shooting? Does it feel painful to shoot? Which direction is your brass ejecting at? Have you found any loads that run better than others? During the failure to feeds, are you running PMAGs?
 
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Hi there!!

About 2 years ago I dropped around 4K on a custom made 18” 308 AR-10. While the gun has an awesome barrel on it and is crazy accurate, I have had the worst time getting it function reliable. From failure to feeds to failure to ejects to bullets getting stuck in what seems to be a tight chamber, I can’t get it to cycle reliably. Not sure if this is due to right tolerances or what. But after taking to the gunsmith a couple times I am contemplating moving on.

with that said, I generally use this rifle mainly for hunting deer/hogs/ varmints anywhere from 100-600 yards and shoot steel out to 900 just for fun. I also run it with an omega full time. I mostly
Value accuracy and the gun not being too heavy or unwieldy given I carry it around a ranch all day and in an out of vehicles. (And obviously want it to function reliably

I have looked at the DD5V3, LT PredatOBR, Wilson Combat and the JP LRP-07.

As ashamed as I am to say it I also value the “coolness factor” a lot and want the rifle to look good. For the reason (I know it’s stupid) but I really don’t care for the JP hand guards and wish you could change them out cause I find them not great looking.

So basically looking for something in 6.5 or 308. Around 16 or 18” and is a good blend of accuracy and weight/maneuverability.

(price isn’t the biggest concern)

would love to hear yalls recommendations or what you have and how you like it!

What is your budget.

While it looks like you like accuracy it looks like the type of shooting you are doing is not calling for a super match type rifle.

Off the three that you mentioned, I think the DD5V3 suits you very well and has a fairly solid reputation. I would also check out the Barrett Rec10. For non Mil issued large frame gas guns, I think that both these rifle like nice options.

The MWS is another option, it can be configured to be around 8.5lbs with the light weight barrel and a 6.5cm, barrel can be mounted in about a minute.

I currently have an MWS, an SR25 ACC, and a Scar 17, and all are really great weapons for their own reasons. If I had to chose one, it would probably be the MWS since its the most flexible.
 
I would not give up on your current AR-10 yet. I have built several, had several issues and fixed them all. Some can be aggravating to find but given you spent that much money I would expand on your issues in this thread to resolve them.
 
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Thanks for all the suggestions everyone!! Really appreciate it.

while I may have understated, I really do love the rifle I have, just getting pretty frustrated with having to leave it at home cause I can’t trust it.

the cycling issue isn’t the biggest concern for me, I know that can be fixed fairly easily, the biggest concern is what’s going on with the chamber.

for some reason bullets are now getting stuck or fitting too tight in the chamber.

a couple things: when I first bought the gun, the bolt would engage and dissengage from battery incredibly easily. The smoothest I have ever felt. And now it isn’t nearly as smooth. Kinda hard to engage and dissengage it.

when I first got the gun, I ran it pretty wet with frog lube, but started running it dry after the frog lube Would get cold and gunk up.

but I have tried 5 different ammos with It:

2 types of trash factory bulk 168 7.62 and both run well and don’t stick in the chamber at all.

Sig Elite match 168 ammo, this ammo sticks in chamber worse than it should, but still able to eject.

168 hand loads. Stuck horribly, left a scuffing at the base of the bullet.

Federal Premium Gold Medal 168. Stuck so bad in chamber it literally unseated the bullet from the brass and got powder everywhere. This happens every time I try the ammo.

FWIW: took it to the gunsmith and they said the headspacing looked good. The folks that made the rifle took a Lilja blank and made it in house, they also matched the bolt to the barrel.

it seems when I got the rifle, it cycled well, bolt would engage and dissengage like butter and no real issues. However, I put about 200-300 rounds of bulk ammo into it before I tried reloading ammo for it and started running into problems. Now it doesn’t cycle anything reliably, and the bullets stick or get stuck, so I can’t think of what could have happened.

hope I didn’t damage anything trying to get stuck rounds out of the chamber or trying to force (unknowingly) bent rounds into the chamber.

I will upload some pictures tonight in case it’s helpful, but that’s where I am at with it!

thank y’all for the advice and recommendations!
 
Thanks for all the suggestions everyone!! Really appreciate it.

while I may have understated, I really do love the rifle I have, just getting pretty frustrated with having to leave it at home cause I can’t trust it.

the cycling issue isn’t the biggest concern for me, I know that can be fixed fairly easily, the biggest concern is what’s going on with the chamber.

for some reason bullets are now getting stuck or fitting too tight in the chamber.

a couple things: when I first bought the gun, the bolt would engage and dissengage from battery incredibly easily. The smoothest I have ever felt. And now it isn’t nearly as smooth. Kinda hard to engage and dissengage it.

when I first got the gun, I ran it pretty wet with frog lube, but started running it dry after the frog lube Would get cold and gunk up.

but I have tried 5 different ammos with It:

2 types of trash factory bulk 168 7.62 and both run well and don’t stick in the chamber at all.

Sig Elite match 168 ammo, this ammo sticks in chamber worse than it should, but still able to eject.

168 hand loads. Stuck horribly, left a scuffing at the base of the bullet.

Federal Premium Gold Medal 168. Stuck so bad in chamber it literally unseated the bullet from the brass and got powder everywhere. This happens every time I try the ammo.

FWIW: took it to the gunsmith and they said the headspacing looked good. The folks that made the rifle took a Lilja blank and made it in house, they also matched the bolt to the barrel.

it seems when I got the rifle, it cycled well, bolt would engage and dissengage like butter and no real issues. However, I put about 200-300 rounds of bulk ammo into it before I tried reloading ammo for it and started running into problems. Now it doesn’t cycle anything reliably, and the bullets stick or get stuck, so I can’t think of what could have happened.

hope I didn’t damage anything trying to get stuck rounds out of the chamber or trying to force (unknowingly) bent rounds into the chamber.

I will upload some pictures tonight in case it’s helpful, but that’s where I am at with it!

thank y’all for the advice and recommendations!
Does the cycling issues occur with factory and reloads or did it start with reloads?
 
If you have factory ammo getting stuck, your chamber is incorrect for the ammo you are shooting. You might have a certain cut of match .308 chamber. Or a miscut chamber which is an easy fix. I’d personally put a headspace gauge in it to know what’s going on with the chamber itself, and I’d want to know what chamber cut the smith did. If it’s a NATO chamber or Palma or whatever.

Fixing a chamber can be as easy as tuning the gas system, relatively speaking. AR-10’s can be harsh on the extraction cycle of fired rounds but you shouldn’t have issues removing unfired rounds.
 
Your chamber pressure has to be pretty high if the bullets are engaging the rifling before firing. Good advice was previously given to send this back to your smith and resolve that issue.
 
The DD5 from Daniel Defense is a good gun. I've shot the piss out of them. My only reservations are the proprietary rail system and charging handle. Top tier would be Knight's Armament Co. SR-25 variants. They're not as good as they used to be, but if you want to impress your friends this is what you get.
 
Did ammo that sticks now get stuck when it was new? Have you kept it clean or is there a nice ring of carbon in there now? The statement on how the bolt does not want to lock/unlock has me wondering how dirty it has become. If OEM rounds always stuck then it might be a short cut throat...make the smith fix it. You put 4K into it...it should run like melted butter.
 
I have friends that have built 308/AR10 guns and that have all sorts reliability issues. They don't listen. If you don't have reliability, then the build is not worth shit IMHO. Go JP full mass carrier and bolt, quality adjustable gas block, and the correct recoil spring and the shit works flawlessly assuming your chamber is GTG. And yes proper breakin and oil always helps!
 
I would fix your current rifle.... especially if it shoots that good.

I would start with a thorough cleaning, chamber, bore, BCG.

Double check the gas system... Gas block secure ? , gas key secure ? , gas rings ok ?

Pics of fired brass would help show if your chamber is "rough".

As others have mention, cycling problems like you have described, of pretty common for Large Frame AR's ... so there is a lot of fixes out there.
 
Just dropped 4.2k on an HK MR762 with mlok handguard. Have yet to receive the rifle (awaiting shipment) but I made my purchase based on their reputation for reliability and quality. I handled one in a shop years ago but decided to go with an SR25 at the time. Based on my memory, the HK fit and finish was more refined that the Kac I owned.

It also helped with my purchasing decision that the US Army selected Hk as their csass and sdmr provider.
 
In think that a chamber cast might show up a short throat.

If the round stuck, then the case came out, but the bullet stayed and spilled powder; it sound like the bullet is seated long enough to jam in the rifling, or that the throat is short enough to catch a factory length bullet's ogive.

We had very similar problems with Savage factory 308 chambers in the 1990's and learned to seat the bullets deeper. For starters try seating the bullet a bit deeper.

Have a good smith check the throat length, and maybe extend it a little, if it registers short.

The scuffing at the case wall bottom may be a second problem, and might respond to a small base F/L resizing die.

Check the first firing handloads as they come out of the die now. If it's there before chambering, it's likely normal. If it's there before the first firing case is resized, the small base die is likely the answer.

When cleaning the chamber, it should end up dry as a whistle. No oil in the chamber, it cruds up and can add to bolt thrust too.

I am not a fan of shorter 308's. The 223 can work well with it, but I believe the short 308 leaves too much performance on the table. For 308, my minimum is 20". I bought mine after my friend bought essentially the same gun, 18", and had problems with cycling and lock back. My 20" worked fine with the original PSA carbine length buffer, and works great with the A2 Tube and JP silent captured 308 buffer assembly. His gas system is midlength, mine is rifle length.

I'm sure there are excellent cycling 6.5 large frame guns out there, I've just never actually seen one. It's the main reason I went with the AR-15 and 6.5 Grendel.

Greg
 
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Sorry for just replying everyone!!

so the thing that makes this more difficult to figure out is that, for the first 6 months of owning the gun, I shot nothing but bulk ammo through it (as I mentioned about 200-300 rounds) dripping wet in frog lube. Ran like a sewing machine.

it wasn’t until I bought that box of Gold Medal 168 when I found out the bullet was getting stuck and unseated in the chamber. So then we made some hand loads and those got stuck in the chamber.

after those two events I sent it to the smith and he said headspacing looked fine on it, and re-sighted with the Sig elite ammo. Also polished the chamber and cleaned the gun thoroughly.
Of course 1st thing I do getting back was drop a live sig round in. Then extract. No problem. Then I dropped one of the live hand loads into it. Got stuck and had to mortar the gun to get it out. Tried a Gold Medal round and it got compelltey stuck.

so sounds like it could be the chamber?

another question out of curiosity, is if I have the chamber reamed or something along those lines, will it effect the accuracy of the gun? I assumed I was having these issues just due to extremely tight tolerances, but to the point the gun doesn’t even work.
 
In think that a chamber cast might show up a short throat.

If the round stuck, then the case came out, but the bullet stayed and spilled powder; it sound like the bullet is seated long enough to jam in the rifling, or that the throat is short enough to catch a factory length bullet's ogive.

We had very similar problems with Savage factory 308 chambers in the 1990's and learned to seat the bullets deeper. For starters try seating the bullet a bit deeper.

Have a good smith check the throat length, and maybe extend it a little, if it registers short.

The scuffing at the case wall bottom may be a second problem, and might respond to a small base F/L resizing die.

Check the first firing handloads as they come out of the die now. If it's there before chambering, it's likely normal. If it's there before the first firing case is resized, the small base die is likely the answer.

When cleaning the chamber, it should end up dry as a whistle. No oil in the chamber, it cruds up and can add to bolt thrust too.

I am not a fan of shorter 308's. The 223 can work well with it, but I believe the short 308 leaves too much performance on the table. For 308, my minimum is 20". I bought mine after my friend bought essentially the same gun, 18", and had problems with cycling and lock back. My 20" worked fine with the original PSA carbine length buffer, and works great with the A2 Tube and JP silent captured 308 buffer assembly. His gas system is midlength, mine is rifle length.

I'm sure there are excellent cycling 6.5 large frame guns out there, I've just never actually seen one. It's the main reason I went with the AR-15 and 6.5 Grendel.

Greg

thanks Greg!

I’m going to try it again this weekend and if same thing happens I’m gonna send to get all the above checked!
Thanks for the help!
 
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Did ammo that sticks now get stuck when it was new? Have you kept it clean or is there a nice ring of carbon in there now? The statement on how the bolt does not want to lock/unlock has me wondering how dirty it has become. If OEM rounds always stuck then it might be a short cut throat...make the smith fix it. You put 4K into it...it should run like melted butter.

i usually keep her pretty clean! I’m gonna clean it up and give it another try this weekend. If same results gonna take to GS and have them look at throat!

thanks for the help
 
AR-10’s need to run wet. Do not run that gun dry. They really don’t need cleaning unless you’re getting dirt or sand in there. Lube that thing up with anything rather than running dry. I use SEAL1 grease.

Your chamber can headspace correctly and you can still be hitting the lands of the rifling too early. The Sig and the bulk ano might be running more pointed bullets that don’t hit the lands on insertion, but the FGMM does. I think it’s the rifling, not the chamber.
 
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Did notice that two of the bottom bolt lugs have some wear and missing metal. This could be from forcing bend bullets into the pipe unknowingly or all the times I had to mortar/ force a live round out ?
 

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Stupid question on my part but it has to do with the consistent issues with handloads vs factory ammo - how are you checking the dimensions on the resized cases?
 
It causes me physical pain to see a dry AR-10. Those guns need to be WET. I lube the shit out of all my AR’s and they run like butter.

Your bolt is messed up and you need to find out what’s up.
 
Stupid question on my part but it has to do with the consistent issues with handloads vs factory ammo - how are you checking the dimensions on the resized cases?
No stupid questions!!
The secondary really is the cycling / consistency. Neither hand loads nor factory are cycling well in it. The primary issue is really why are the rounds tight / getting stuck in the chamber.
And as for the hand loads. This isn’t very helpful. But my dad reloaded a bunch of 308 rounds and that’s what I used so not sure on how he spun them up, but I’ll ask and report back!
 
It causes me physical pain to see a dry AR-10. Those guns need to be WET. I lube the shit out of all my AR’s and they run like butter.

Your bolt is messed up and you need to find out what’s up.

okay that is great to know!! As I mentioned I ran it soaking wet with frog lube when I first got it, it ran really well, but when I was hunting it got cold and turned into just a thick gunk. Any lube you reccomend?

do you think the bolt is messed up based on the images and the lugs being scuffed up or just in general because of how the rounds are sticking in the rifle?

I am thinking about ordering a JP BCG and throwing it in there, but that’s an expensive thing to do, if it’s really a problem with the chamber/ throat.
 
That rifle is filthy,clean it and get a good look at that bolt
I’ll get it cleaned and give it a try again this weekend and see how that does.

problem is, it feels like it needs to be cleaned after every 10 shots suppressed 😂.

I guess I’m just not used to how AR10’s like to operate, causeI have an old of the shelf bushmaster in 223 that I have shot hundreds and hundreds of rounds suppressed without cleaning without a single issues. I guess they are different beasts.
 
Sounds like that bulk 147 has a shorter base to ogive measurement than the FGMM 168’s.

I know the smith said it headspaced properly, but that’s only measuring the cases...not the throat and what the throat was reamed for.
After cleaning to ensure there is no carbon ring, if you can run that cheap 147’s without issue, but have trouble with 168’s/175’s, it would appear your smith used the wrong reamer for the match bullets you want to use.
 
Do you really need an AR platform for what you're doing? I built a 6.5 CM with an F1 receiver and love it, but needed the AR for fast followup shots as I'm primarily killing pigs. I've had plenty of issues with it, but is generally reliable and very accurate so long as I clean it after every outing. Suppressed and DI ARs I've found over the years are not the most reliable. Have a Sig MCX VIRTUS and it is the first suppressed AR that performs like I feel it should for night hunts with NV and routinely going through 30+ rounds a night, still haven't cleaned it yet.
Would a bolt gun serve your needs better? If want an AR platform, my experience says piston is what you're seeking if shooting suppressed consistently.
 
okay that is great to know!! As I mentioned I ran it soaking wet with frog lube when I first got it, it ran really well, but when I was hunting it got cold and turned into just a thick gunk. Any lube you reccomend?

do you think the bolt is messed up based on the images and the lugs being scuffed up or just in general because of how the rounds are sticking in the rifle?

I am thinking about ordering a JP BCG and throwing it in there, but that’s an expensive thing to do, if it’s really a problem with the chamber/ throat.
1: Your gun is *not* dirty, and you're going to cause way more harm than good by cleaning it all the time. Don't overclean guns. I have thousands of rounds through my AR's and I don't clean them. I lube them, and I get lube on my glasses and my face and weeping out between the receivers. Run them wet. There really isn't much to clean, as long as you're running them wet enough that carbon isn't baking onto surfaces, the carbon just discolors lube like oil in an engine. Run an engine after an oil change for 50 miles and it's still good oil but it's black as night. Same thing here. Just never run an AR dry. Vickers did a demo on overlubing by dunking an entire rifle in a bucket of motor oil and then ripping on it.

2: Yeah your bolt is jacked up, and might be part of the problem. I'm not sure what caused that but even after my AR-10 had issues running too fast and smashing into cases, it didn't do harm to the bolt.

3: That gun needs to be broken in. Grab some mil surp if you have it, and go shoot 300 rounds through it.

4: You need to confirm your throat dimension with your gunsmith. A chamber can headspace correctly, but the throat portion in the rifling can be cut for certain bullets. If the ogive, the fat part, of your bullet is longer than intended, it will engage the rifling when the bolt closes and you run into the issue you have here.

5: AR's do run fidgety when it gets really cold, especially with the grease I run. I just got some Cherrybalmz winter lube and some Breakthrough high purity oil to try out, both look like they're going to run well out hunting in the snow. I haven't tried either to have feedback on them.
 
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3 rifles. All wet. I try to keep lube off the forward bolt face and out of the chamber, and off the firing pin, otherwise it’s pretty much fair game on an AR. Lube in the buffer tube, lube the bolt and gas rings, lube the heck out of the bolt.
 

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I think the first thing besides cleaning and lubing is to buy this: https://www.midwayusa.com/product/1012747079?pid=570611

and this: https://www.midwayusa.com/product/1012753414 make sure you select a .308 Win for the case.

Then you can determine with whatever bullet you want what your OAL of reloads needs to be before they hit the lands. Then if you've got a short throat you'll know by how much. Since the throat is going to erode with time anyhow, you have a self-correcting problem. If you know then that you'll hit the lands with an OAL of say 2.795 using a 168 SMK and let's say that FGMM 168s measure 2.810, now you'll know WHY you're sticking bullets.

At this point you have no idea why it does what it does. The smith is checking with headspace gauges which only measure from the datum line on the shoulder, not OAL. He's getting a number of 1.630 or slightly larger and happy with it.

If cases or reloaded cases are sticking near the head and not chambering they probably need to be run through a small base die. That said it seems unlikely since most factory stuff works.

You can simply seat factory ammo deeper, not crazy deep but sensibly enough to function in your rifle. Fire a shot and make sure you're not flattening primers or showing any other signs of pressure. If your dad or whoever wants to make up some reloads just make sure the OAL is short enough to have some jump to the lands with the bullet you're using and realize that you can't run max pressure loads at a shortened length.

You could try and find another smith familiar with lengthening the throat. Personally I'd just keep measuring the throat and shoot the piss out of it. That barrel ought to be around for 10k rounds.

I don't think you've ever stated, does this rifle have an AGB? If not, I'd get a Superlative Arms which vents off some of the excess gas which would help running it suppressed.
 
This is a headspace gauge.

If you will note, it does not include a neck portion. This gauge, and ones very much like it, is what gunsmiths use to check headspace.

What it does has nothing to do with the chamber neck or rifling throat. A rifle can pass the headspace test and still have issues with the throat/rifling entry. The headspace test does nothing to do with neck length or bullet seating/rifling entry.

My best guess is that the rifle's chamber/throat is not deep enough into the rifling to allow a standard dimension cartridge to chamber without the bullet engaging the rifling. If it is shorter enough, it will grip the bullet enough that extracting the unfired cartridge will generate enough force to retain the bullet as the case is extracted.

This is precisely the issue you are experiencing. This may also be related to the accuracy issue, it may not; but it is a definite problem and needs to be addressed.

As noted above; standard issue 147-150gr (M-80 Ball ammo equivalent) cartridges utilize bullets with an ogive that does not (usually) contact the rifling under any reasonable conditions. They will most likely not help disclose or diagnose this problem.

Greg
 
The thing to consider if you find a short leade (distance to lands) is that this is only a problem if the rounds are long enough to engage the rifling too deeply when chambering. Since you handload, you should have the means to reseat the bullets deep enough to eliminate the problem,

There are positives and negatives associated with this.

Positive:

A short throat can have a longer lifespan, since it has further to recede before it becomes problematic. I specifically ordered my L-W 260 Rem barrel with a shorter throat for just this reason. I bought it in 2003, it has several years worth of full season 1000yd F Open wear on it, and still shoot great; I just make sure there are no frivolous rounds going down the bore.

Negative:

Seating deeper reduces internal case volume, and can cause pressure issues, some of which can be quite significant (I.e. blown primers). This could require reduced charges, which could likewise reduce performance.

You may want to consider these points.

Greg
 
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Sorry for just getting back, it’s been a crazy couple weeks but just got out to farm to shoot today. I got her working fairly reliably after messing with the gas a lot. But I sharpied some bullets to see what was going on and here are the photos of before and have chambering the round. What would this tell me?
 

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May be worth trying the Hornady OAL guage. Sounds like a throat lands issue effecting different bullets. Some jam, some dont.

Whats the differemce between the Sig and GMM bullets?

Might try a lighter smaller bullet.
 
Sorry for just replying everyone!!

so the thing that makes this more difficult to figure out is that, for the first 6 months of owning the gun, I shot nothing but bulk ammo through it (as I mentioned about 200-300 rounds) dripping wet in frog lube. Ran like a sewing machine.

it wasn’t until I bought that box of Gold Medal 168 when I found out the bullet was getting stuck and unseated in the chamber. So then we made some hand loads and those got stuck in the chamber.

after those two events I sent it to the smith and he said headspacing looked fine on it, and re-sighted with the Sig elite ammo. Also polished the chamber and cleaned the gun thoroughly.
Of course 1st thing I do getting back was drop a live sig round in. Then extract. No problem. Then I dropped one of the live hand loads into it. Got stuck and had to mortar the gun to get it out. Tried a Gold Medal round and it got compelltey stuck.

so sounds like it could be the chamber?

another question out of curiosity, is if I have the chamber reamed or something along those lines, will it effect the accuracy of the gun? I assumed I was having these issues just due to extremely tight tolerances, but to the point the gun doesn’t even work.
Not sure what your problem is with the chamber, but don’t use Frog Lube.

That stuff is jam-o-matic sauce. Saw it shut down a Noveske in one of my Winter DM Courses several years ago. Felt like someone had poured fine sand all over inside the action, but we were surrounded by snow and ice. The guy had lubed it with Frog Lube.
 
Did the gunsmith use a tight chamber reamer meant for a bolt-action match rifle?

Did you use a Hornady LNL or Stoney Point gage to check your freebore for factory ammo?

A semi-automatic rifle that won't chamber and fire factory ammo is useless unless you're loading your own specifically for that rifle.

A tight chamber, short throat, self-loading function, no lube, and a suppressor is darn near a perfect recipe for stoppages, regardless whether a factory or custom-built rifle.
 
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