What the hell just happened?

[High Desert duck]

COL is fine ,,, no clue what neck tension ,,, just resized and reloaded COL for the bullet Mnfgr is correct

The easy way to determine neck tension is to measure the neck If a sizeed case prior to seating the bullet and then after seating the bullet. I’ve loaded 1000s of rounds for a semi 6.5 CM, and I ran around .003. But you’ll want to check for bullet setback or movement (due to recoil and or Feeding) by assembling a couple of empty rounds, no powder no primer just sized and BulleT seated. Feed one of those dummy rounds and measure COAL before and after loading into the chamber. It should not move. Now next time at the range run one live and the dummy In the magazine. Measure it before it feeds. COAL should not change.

I also never used small base dies. I was using a Redding type S body die. What does are you using. Also if you replacing the bolt look at grabbing a JP high pressure bolt. It won’t let you run higher pressure but will support the primer better at normal pressure.

 

[Yondering]

If you are not using a Small Base sizing die... there is your problem!

The die MUST have engraved on it "Small Base" or S.B. depending on the maker.

On ANY semi rifle, reloading requires a small base die.

This is absolutely not correct. You may have always done it that way without issues, but that does not mean all semi auto rifles have to be loaded that way. Normal FL dies are fully adequate most of the time.

Small base dies are only needed with very tight chambers, regardless if they are in bolt actions or semis. Those tight chambers seemed to be more common in semi autos in years past, but most manufacturers have gotten away from that by now. Most modern semi auto rifles do not need to be loaded with small base dies, as the many thousands of us who use FL dies know.

Also - the rifle discussed in this thread did not need to have the headspace checked with go/no-go gauges, as claimed earlier. People seem to forget that headspace is a relative measurement between the chamber and the cartridge; when handloading, adjustment of the FL sizing die sets the headspace so it really doesn't matter where the rifle's chamber is relative to spec if the discussion is about handloads. What does need to be measured is headspace via something like the Hornady case comparator or other similar tools; that tells you the headspace of your sized brass relative to the rifle in question.

 

[sirhrmechanic]

This is absolutely not correct. You may have always done it that way without issues, but that does not mean all semi auto rifles have to be loaded that way. Normal FL dies are fully adequate most of the time.

Small base dies are only needed with very tight chambers, regardless if they are in bolt actions or semis. Those tight chambers seemed to be more common in semi autos in years past, but most manufacturers have gotten away from that by now. Most modern semi auto rifles do not need to be loaded with small base dies, as the many thousands of us who use FL dies know.

Also - the rifle discussed in this thread did not need to have the headspace checked with go/no-go gauges, as claimed earlier. People seem to forget that headspace is a relative measurement between the chamber and the cartridge; when handloading, adjustment of the FL sizing die sets the headspace so it really doesn't matter where the rifle's chamber is relative to spec if the discussion is about handloads. What does need to be measured is headspace via something like the Hornady case comparator or other similar tools; that tells you the headspace of your sized brass relative to the rifle in question.

Having gone and read a bunch more ‘recent’ info on FL dies... I won’t disagree. One of those Back in my day things apparently!

And the headspace thought was early in the discussion before more info started to come in. So 100 percent agree with you there. We were throwing a lot of things around in the first page of diagnosis... and headspace seemed a thing to check... but not before some other things as you saw the discussion evolve. And later was obviously not a factor.

I will have to try some FL dies out on AR’s. But my first CAR-15 Colt in 1988 wouldn’t and still won’t run without them. And I don’t thing My FAL or CETME will. But now I’ll have to try!

But definitely going to try out some loads with regular dies. Who says you can’t teach an old dog new tricks! And this thread sent me off to read up on fl fies in semis. So all good!

Cheers,

Sirhr

 

[Yondering]

Thanks man ,, I appreciate that .... this is my first build and the Upper came assembled , so I'm sure that the head space is fine,, but the BTO is something that I'm very new to . No clue how to do that . But I'm thinking i need to PULL all remaining loads and start over . I don't need to be wearing an eye patch next time . or worse. So do I Mic. from the base to the top of case neck or base to start of Ogive? How the fik do you do that ? Over? lol

I see you got some answers on this, with good pictures, but I didn't see where that poster actually told you how to use those measurements he said you need.

Fortunately there is an easier way, this is more complicated to describe than it is to actually do; it's really pretty quick and simple. You just need a locking collar on your cleaning rod and a blunt tip for the rod. This will be used to measure the max OAL and max cartridge base to ogive for your rifle with a particular bullet. The locking collar can be a simple plastic disc with a set screw, or something like that. I use a brass bore guide (installed backwards) that I drilled and tapped for a set screw, and for a blunt tip I use a caliber-correct brass jag with the pointed tip filed off.

With the bolt closed in your rifle:
- Insert the cleaning rod (with blunt tip attached, and locking collar on the rod) in the muzzle until the tip of the rod stops against the bolt face. Hold it in that position, and slide the locking collar down against the muzzle (or muzzle device). Lock the collar in place. That is your zero position, any gap you measure between the collar and muzzle will indicate the same gap between the rod tip and bolt face. Remove the rod for now, but don't move the locking collar.
- Now load an empty sized case (no primer or powder) with the bullet you want to use, but seat it extra long. We want the bullet seated out so long that the round cannot chamber; usually just barely seating the bullet into the case works well.
- Insert your dummy round into the chamber, and gently ease the bolt against it. It should not chamber fully; if it does you seated the bullet too deep or the chamber throat is too long for that bullet. Let the buffer spring push the bolt against the cartridge and hold it in place.
- Now insert your cleaning rod again, carefully so you don't dent the bullet tip. With the blunt tip of the rod against the bullet nose, measure the gap between the muzzle and the locking collar with your calipers. This measurement is the max OAL for that particular bullet in your chamber.

Carefully remove the round from the chamber; you may need to press the bullet out of the throat with the cleaning rod, but be careful not to dent the tip of the bullet.

If you take that dummy round and carefully adjust your seating die to seat the bullet to exactly the OAL you measured in the barrel, you now have a dummy gauge that is matched to your chamber. You can measure cartridge base to ogive on this dummy accurately, and use that to compare to other loaded rounds with the same type of bullet. You'll find in your loaded ammo that OAL varies, but as long as the CBTO measurement is consistent it doesn't matter much.

Hope that helps without being too long winded or confusing.

 

[Yondering]

One other thought on the rounds that wouldn't chamber from the magazine:

While it's more likely the cause was either poor sizing die adjustment or bullets seated to long, a third possibility is loaded neck diameter too large for the chamber. If the chamber neck is the same size or slightly tighter than the loaded round, the cartridge will stick when chambering, and if forced in place and fired it can cause excessive pressure.

It doesn't sound like that's the case, but it's easy to check - take a fired case and see if a bullet will slip into it. If the neck is too tight to slide a bullet in easily by hand (assuming it's round and not dented of course), there may be a neck diameter issue.

 

[little_scrapper]

What Yondering said is technically correct. However keep in mind that the pressure from the bolt spring will likely be "jamming" the bullet into the rifling a couple/few thousandths.

"MOST" people consider jamming far less than ideal as it can cause pressure spikes. Therefore, IMO, that max OAL may be a tad long.

 

[Yondering]

What Yondering said is technically correct. However keep in mind that the pressure from the bolt spring will likely be "jamming" the bullet into the rifling a couple/few thousandths.

"MOST" people consider jamming far less than ideal. Therefore, that max OAL may be a tad long.

A thousandth or so is my experience. But that is just to give a relative point to work from; there are very few cases with a large frame AR where you can jam bullets to the rifling and have them fit the mag. This measurement is a reference to know if you're jumping .050", .100", etc, and it doesn't much matter at AR seating lengths if that's actually .050" or .051". If you're actually trying to seat right at the lands in a bolt gun it can matter, but then you don't have a buffer spring to deal with anyway and can more gently seat the bullet against the lands.

If you are someone with a special setup that will jam bullets at mag length, presumably you know about this stuff and understand about jump and chasing the lands, etc. Speaking of chasing the lands, the method I described is an easy way to measure how far the lands have moved, if you keep records of when you set the first dummy round...

If a guy really wants to be anal about it, you can remove the upper and just use a rubber band or piece of electrical tape to hold the bolt carrier in position, like some of the benchrest guys do.

 

[nn8734]

@Yondering, assuming you are describing how to find “jam length” (ie where case head to Ogive length = 0 bullet jump) to dial in desired jump, here is the process using the Hornady OAL gauge and modified case (.308 is used but I would think Hornady makes one for 6.5CM.

@MAGA4LIFE

I allueded to this in the “upstream step” in my post [see 2nd paragraph in post #66 on page 2] the pics on the earlier page however provided no specific instructions as magazine length usually prevents one from getting most bullets close the lands. To get the jam length measurement, do the following AFTER you ogive-sort your bullets:

Step one: acquire the Hornady oal gauge and the modified case corresponding to your cartridge (6.5 creedmoor; $20 or so)

Step 2: Screw the modified case onto the threaded end of the OAL gauge and insert one of your bullets from any one of the Ogive sorted “buckets”

Step Three: Insert the assembly case-first into the rifle (I’m showing this on my SR25 so as to show how to do this on a semi)

Use the plunger rod (gray) to force the bullet to the lands then tighten the knurled retaining screw.

Step 4: Measure the case head to Ogive with the oal gauge, your bullet comparator using your dial calipers.

Record this number. Repeat the above steps a couple times with the same bullet to be sure your measurements are consistent.

Step Five: Set your bullet seating die on a dummy round such that the case head to Ogive measurement is the same - this is the jam length for those bullets with that same bullet base to ogive length recorded during Ogive sorting done in the previous steps.

Step Six: Adjust your seating die so that the bullet is seated based on the amount of jump you want. For semis, I typically use .030 jump if I can get it without running out of room in the mag...in the gun above, I’m jumping .055” as that’s the closest I can get before I run out of room in the magazine.

Post here if you need any clarification.

 

[little_scrapper]

Im new. Just started reloading last year. Have loaded a total of about 200 rounds so far. LOL but I am also one of those guys that absolutely devours information about a subject like this. That is because I understand the dangers of working with energetics and a little knowledge is dangerous. Its what you dont know that will kill you.

I have done a lot of reading and I am still working on my first pet load for my LaRue. I have a couple charge weights worked out for 168 & 175 gr SMKs. I now need to do a short ladder right around that weight and also vary the seating depth or jump.

I read alot.

 

[little_scrapper]

nn8734. How do you tighten the knurled knob when its inside your upper like that?

I have the Hornady and the same problem. The damn thing isnt long enough for my LaRue. Instead of tightening it into the "hole" that its made to screw into; I have to hang that knurled knob off the back and even then I can barely reach it to tighten it down. It probably fits an AR15 just fine but I dont load for AR15. I found 3 off the shelf ammos that shoot sub MOA plus I get plinking 556 for 10 cents a round. Ae 223, M193 and others. Couldn't even even come CLOSE reloading for those prices.

 

[nn8734]

nn8734. How do you tighten the knurled knob when its inside your upper like that?

I have the Hornady and the same problem. The damn thing isnt long enough for my LaRue.

Good question, should have mentioned it in the post. I use a small flat head screwdriver and gently “turn” it until tight. I always repeat the process a couple times to ensure I’m getting the same result.

@MAGA4LIFE; FYI

 

[little_scrapper]

Goes to look at mine and see if I didnt notice the screw driver slot. BRB.

OK I looked. NOPE. I dont have a screw driver slot. However I did measure it and the OD of the guide rod is .370". I just need to make a longer collar that will stick out farther. The back end of which will have a smaller ID to closer match the pushrod. Simple.

 

[nn8734]

Goes to look at mine and see if I didnt notice the screw driver slot. BRB.

There isn’t a slot but the knurling on the screw will allow the screwdriver blade to grip it enough to enable you to tighten it sufficiently. It will be a bit awkward at first but you will get the hang of it...

 

[little_scrapper]

Got it. That will work until I make a new collar at work.

Now back the the OP. Yea... Ummm 10gr over max? Yea, that'll do it. Although so far I have never loaded for anything but 308. 6.5 must still have plenty of room in the case. 41ish grains of Hodgdons 4895 fills a M118LR case right up into the shoulder. I should fill one to the top just to see how much it would hold completely filled. Probably about 43gr max. Hard to over load a the NATO brass I guess.

 

[TheGerman]

Get a case guage and put one of your fired cases in it to see how much it laughs at you.

Oh, and....

 

[2aBaC̶a̶]

As a reference my 6.5CM and a 147 hits the lands at BTO of 2.263 which makes the OACL 2.910 and too long to fit in a standard mag which I measure at 2.80.

 

[Yondering]

@Yondering, assuming you are describing how to find “jam length” (ie where case head to Ogive length = 0 bullet jump) to dial in desired jump,

Yes, same as what you described, mine is just a quick and easy way to do it without the special tool or caliber-specific adapter. I got it from a benchrest article somewhere quite a while ago. Those guys rig up a rubber band or something to hold the bolt closed, but the AR platform has that part built in.

Regardless of the method used to find the lands - I keep a dummy cartridge for each bullet I load in the box with the dies for that rifle, with pertinent info like max OAL to lands written on the cartridge in sharpie.

 

[stevieb92]

nn8734. How do you tighten the knurled knob when its inside your upper like that?

I have the Hornady and the same problem. The damn thing isnt long enough for my LaRue. Instead of tightening it into the "hole" that its made to screw into; I have to hang that knurled knob off the back and even then I can barely reach it to tighten it down. It probably fits an AR15 just fine but I dont load for AR15. I found 3 off the shelf ammos that shoot sub MOA plus I get plinking 556 for 10 cents a round. Ae 223, M193 and others. Couldn't even even come CLOSE reloading for those prices.

Hornady makes a tool for use in semi rifles...

https://www.amazon.com/Hornady-C1550-Lock-N-Load-Length-Curved/dp/B000PD6SD0

 

[KAIFS]

Fulton Armory

Our M14 gunsmith at Fulton Armory handcrafts the most exceptional rifles across the entire United States. Shop your source for service rifles, parts, tools, and more today at Fulton-Armory.com.

www.fulton-armory.com

GET yourself a set.

1. GO: Corresponds to the minimum chamber dimensions. If a rifle closes on a GO gauge, the chamber will accept ammunition that is made to SAAMI’s maximum specifications. The GO gauge is essential for checking a newly-reamed chamber in order to ensure a tight, accurate and safe chamber that will accept SAAMI maximum ammo. Although the GO gauge is necessary for a gunsmith or armorer, it usually has fewer applications for the collector or surplus firearms purchaser.
2. NO-GO: Corresponds to the maximum headspace Forster recommends for gunsmiths chambering new, bolt action rifles. This is NOT a SAAMI-maximum measurement. If a rifle closes on a NO-GO gauge, it may still be within SAAMI specifications or it may have excessive headspace. To determine if there is excessive headspace, the chamber should then be checked with a FIELD gauge. The NO-GO gauge is a valuable tool for checking a newly-reamed chamber in order to ensure a tight and accurate chamber.
3. FIELD: Corresponds to the longest safe headspace. If a rifle closes on a FIELD gauge, its chamber is dangerously close to, or longer than, SAAMI’s specified maximum chamber size. If chamber headspace is excessive, the gun should be taken out of service until it has been inspected and repaired by a competent gunsmith. FIELD gauges are slightly shorter than the SAAMI maximum in order to give a small safety margin.

 

[2aBaC̶a̶]

It's an AR, theres really no point. If factory ammo shoots, headspace is fine.

what he could really use is an ammo checker for his reloads.

Ammo Checkers™ Single Caliber

260 Remington, 6.5x55 S, 350 Legend, 327 Federal, 38 Super, 45 ACP, 6.5 PRC.Lyman’s multi-caliber Ammo Checkers have proven to be extremely popular with reloaders since their introduction last year. Ammo Checkers are gauges that verify the quality and consistency of both reloaded and factory...

www.lymanproducts.com

 

[Yondering]

Fulton Armory

Our M14 gunsmith at Fulton Armory handcrafts the most exceptional rifles across the entire United States. Shop your source for service rifles, parts, tools, and more today at Fulton-Armory.com.

www.fulton-armory.com

GET yourself a set.

1. GO: Corresponds to the minimum chamber dimensions. If a rifle closes on a GO gauge, the chamber will accept ammunition that is made to SAAMI’s maximum specifications. The GO gauge is essential for checking a newly-reamed chamber in order to ensure a tight, accurate and safe chamber that will accept SAAMI maximum ammo. Although the GO gauge is necessary for a gunsmith or armorer, it usually has fewer applications for the collector or surplus firearms purchaser.
2. NO-GO: Corresponds to the maximum headspace Forster recommends for gunsmiths chambering new, bolt action rifles. This is NOT a SAAMI-maximum measurement. If a rifle closes on a NO-GO gauge, it may still be within SAAMI specifications or it may have excessive headspace. To determine if there is excessive headspace, the chamber should then be checked with a FIELD gauge. The NO-GO gauge is a valuable tool for checking a newly-reamed chamber in order to ensure a tight and accurate chamber.
3. FIELD: Corresponds to the longest safe headspace. If a rifle closes on a FIELD gauge, its chamber is dangerously close to, or longer than, SAAMI’s specified maximum chamber size. If chamber headspace is excessive, the gun should be taken out of service until it has been inspected and repaired by a competent gunsmith. FIELD gauges are slightly shorter than the SAAMI maximum in order to give a small safety margin.

For anyone loading their own, there is really no point to this other than ensuring the rifle is safe to shoot with factory ammo. Beyond that, it has no value.

 

[19Scout77]

This thread has an unbelievable amount of diarrhea of the mouth or in this case keyboard. OP...ignore every single piece of advice in this post and either stick with factory ammo or learn the proper way to reload from step one. People who have been loading PROPERLY for 4+ years do not make this type of rookie mistake. Have your rifle reassembled and checked by a proven gunsmith, test with factory ammo...and for gods sake do NOTHING suggested regarding bullet depth, crimp, small base dies, etc etc etc until you first get some serious remedial reloading instruction. Your questions in this thread clearly demonstrate a fundamental lack of understanding even the most basic reloading concepts.

 

[MontanaMan]

Also - the rifle discussed in this thread did not need to have the headspace checked with go/no-go gauges, as claimed earlier. People seem to forget that headspace is a relative measurement between the chamber and the cartridge; when handloading, adjustment of the FL sizing die sets the headspace so it really doesn't matter where the rifle's chamber is relative to spec if the discussion is about handloads. What does need to be measured is headspace via something like the Hornady case comparator or other similar tools; that tells you the headspace of your sized brass relative to the rifle in question.

This ^^^^^ although I use a different tool, the RCBS Precision Mic

Precison Mic

On any new barrel, I always check with a Go Gauge, just to be sure, & then I have a series of dummy brass made up (sized) in .001" increments from minimum chamber (HS) that I can use to verify exactly how much HS from minimum the rifle has. I do this by hand with the barrel off the gun & with the exact bolt that will go with the gun. (To do it right, you either need to remove the ejector & the extractor from the bolt or you need to cut the dummy brass out so as to not compress the ejector or you will get false info)

And then, of course, measure fired virgin brass to confirm what HS dimension is to resize the brass for that particular gun to.

I also have a setup as Yondering describes later for verifying max COAL......................works just fine.

Absent the correct tools, as well as sufficient knowledge to load ammo to correct HS dimensions for a given rifle can be trying & does lead to problems such as the OP has had. He was lucky IMO.

MM

 

[meestermeetch]

I have had a similar issue (and outcome and fucked up brass) with the isreali IMI 308 in a PWS MK216 running suppressed. For reference I do not reload.

My issue stemmed from neck tension and having the rounds end up compressed as they entered the chamber, thus spiking pressures and causing the gun to not be "in time" so to speak. Unlocking while still high pressure in chamber so brass ballooned near the case head.

The reason I say this is that evidently loading for semis vs bolts is very different and even factories fail to realize (or tell consumers) this.

It seems like you got it sorted and stayed safe. I kept the brass from the event so I always remember things could have gone far worse, be smart and have prospective.

 

[clcustom1911]

So how the hell did i get SOOOOOO much pressure......

I used 43.5 grain of Varget to push HORNADY 147 gn ELD Match

That's massively overcharged. Like 9 grains over max in the Hornady book and 8 grains over max for the 142 SMK in the Sierra book. I think you found your answer.

 

[TheGerman]

So how did you come up with that power charge?

I mean, you didn't just randomly select a number, so where did it come from/what was your thought process?

Did you read the data from a different powder or something?

 

[2aBaC̶a̶]

So how did you come up with that power charge?

I mean, you didn't just randomly select a number, so where did it come from/what was your thought process?

Did you read the data from a different powder or something?

Dyslexia is a mother fucker when reloading.

 

[Gatorshark]

Tolerance stacking. Too much charge, Winchester brass, carbon buildup in chamber/bolt interface and throat, and oh yeah; Winchester brass.
from the looks of the fired brass, definately would benefit from some "polishing" of the barrel extension ramps and barrel chamber maybe?

 

[nn8734]

So how did you come up with that power charge?

I mean, you didn't just randomly select a number, so where did it come from/what was your thought process?

Did you read the data from a different powder or something?

He hasn’t been around since Sunday....may have exited stage left, not unlike Saclee Rhino in that gear queer thread....

 

[TheGerman]

He hasn’t been around since Sunday....may have exited stage left, not unlike Saclee Rhino in that gear queer thread....

Or, for a huge plot twist......its Saclee Rhino's other account.

 

[nn8734]

Or, for a huge plot twist......its Saclee Rhino's other account.

Wouldn’t surprise me in the least. Maybe he has one account for every cluster fuck perpetrated.

 

[carbonbased]

So how the hell did i get SOOOOOO much pressure that it completely extruded the brass into the ejector hole,, thats a BOATLOAD of pressure, and i had to PRY that SOB off the bolt face. was the charge I used 43.5 grain of Varget to push HORNADY 147 gn ELD Match

Dis the prob. Bullet just don’t have enuf juiz. You need to more grans, and this tyme, use some of pistol powda.









(don’t do this. really)