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  #1  
Old 07-10-2018, 11:47 AM
DougS DougS is offline
 
Join Date: Oct 2009
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Default Bula barrel issue - chamber/throat problem

Last November 2017 (Black Friday sale) I purchased from Bula Defence a M21DMR barreled receiver. The first time I took it out to the range I had nothing but problems with chambering and extraction of the rounds. Basically after 10 rounds, and tearing the rim off two, and having to use a cleaning rod to remove a case from the chamber, I gave up.
It turns out the rifle had one of the 08/17 barrels identified in an earlier post that had problems. After contacting Jeff at Bula, the rifle was sent back for rework. When I received the rifle back, it appears the same barrel was returned, but the chamber appeared to be polished. I asked what was actually done to the barrel, but received no response.
I took it out to the range July 2nd. I fired about 15 rounds of LC17 ball and had no issues. In firing my reloads (LC unfired cases, 39.0gr IMR 3031, Nosler 168gr HPBT CC at 2.8 COAL) I had the same problems as before.
Long story short, I've contacted Bula again, but again no response. Investigating this issue the headspace is at least 1.634 as the bolt closes on my Forster No/Go .308 gauge. But I believe this issue is the throat being cut only for the short 147gr ball bullet, and the longer bearing surface bullets outside the case are jamming into the rifling causing the bolt not to fully close, and likely causing too early extraction in the firing cycle, before the case contracts.
Has anyone else had similar problems with Bula barrels? I could just run my pull thru reamer and open up the throat, but I'm not too happy with the no/go chamber as it is.

Last edited by DougS; 07-10-2018 at 12:05 PM.
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  #2  
Old 07-10-2018, 12:14 PM
nf1e nf1e is offline
 
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Yep, I have used a bunch of Bula 22" NM barrels without a problem.Just wondering if you trimmed the cases to a .308 case trim length of 2.005 or less?
If so, you should be having no problems as long as you are sizing your cases properly.
I like to keep my shoulders back .004 to .006 from chamber headspace.
If as you say, the bullets are up against the rifling I would worry more about over pressure.
I use a reamer that cuts the throat .010 longer on mine than standard .308.
I shoot a lot of M118.
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Last edited by nf1e; 07-10-2018 at 12:17 PM.
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Old 07-10-2018, 12:26 PM
Quarterbore Quarterbore is online now
 
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If your bullet is up against the rifling the issue may well be chamber pressure. Note that brass cases doesn't contract after firing, at least not quick enough for ejection in a gun. I am not an expert on the m14 but my suggestion would be to look for a gunsmith that can look at the chamber and perhaps give it more throat to allow you to use longer bullets if that is your desire.

Certainly, you would think a barrel manufacturer would have this figured out but a chamber casting will give you actual measurements you can work off or there are gauges you can get to measure your throat to find an ogive that works with your desired bullet.

Careful with your long bullets until you get it figured out and looked at as my concern is that your pressures are spiking.
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Old 07-10-2018, 12:50 PM
DougS DougS is offline
 
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Quote:
Originally Posted by nf1e View Post
Yep, I have used a bunch of Bula 22" NM barrels without a problem.Just wondering if you trimmed the cases to a .308 case trim length of 2.005 or less?
If so, you should be having no problems as long as you are sizing your cases properly.
I like to keep my shoulders back .004 to .006 from chamber headspace.
If as you say, the bullets are up against the rifling I would worry more about over pressure.
I use a reamer that cuts the throat .010 longer on mine than standard .308.
I shoot a lot of M118.
The cases are trimmed to slightly less than than what the RCBS trim die would take them to, but in a Giraud. I have no issue with this load in any other M1A/M14/M21 I own, and I have a few. I have checked the cases in the chamber, and based on the visible case before the rim taper, they are consistent with the LC17 ball. The loaded 168 rounds show almost 1/16" more case above the rim taper, so it has to be the throat and the heavier/shorter ogive HPBT bullets, not letting the case fully enter the chamber.
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  #5  
Old 07-10-2018, 12:54 PM
DougS DougS is offline
 
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Quote:
Originally Posted by Quarterbore View Post
If your bullet is up against the rifling the issue may well be chamber pressure. Note that brass cases doesn't contract after firing, at least not quick enough for ejection in a gun. I am not an expert on the m14 but my suggestion would be to look for a gunsmith that can look at the chamber and perhaps give it more throat to allow you to use longer bullets if that is your desire.

Certainly, you would think a barrel manufacturer would have this figured out but a chamber casting will give you actual measurements you can work off or there are gauges you can get to measure your throat to find an ogive that works with your desired bullet.

Careful with your long bullets until you get it figured out and looked at as my concern is that your pressures are spiking.
I agree the throat needs opened up, but as the barreled receiver is less than a year old, the manufacturer should address the issue in my opinion, and not me having to spend more, or to do it myself for that matter. I have a reamer set, having barreled a few receivers previously. But again I can't believe others have not also had this problem, or am I just the lucky one.
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Old 07-10-2018, 01:04 PM
nf1e nf1e is offline
 
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  #7  
Old 07-10-2018, 01:19 PM
Deuceguy Deuceguy is offline
 
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Doug, what dies are you using?
I have LC ball and I also reload with M118LR. I cut my match chamber at 1.631, which is a Bula barrel. After FTE issues, and some advice to get a RCBS mic gauge, I found out my lee dies weren’t cutting it for the chamber I had. I also had the same problem on a Springfield M1A. The lee dies were setting the headspace too long.
I purchased RCBS competition dies and have never had a problem. The RCBS mic gauge show that LC ball and my reloads are the same headspace.
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Old 07-10-2018, 01:22 PM
Deuceguy Deuceguy is offline
 
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I wouldn’t open that throat up either. And there is nothing wrong with polishing the chamber. You wouldn’t believe me if I told you what method is used by the most experienced barrel makers out there.
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Old 07-10-2018, 02:16 PM
DougS DougS is offline
 
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Quote:
Originally Posted by Deuceguy View Post
Doug, what dies are you using?
I have LC ball and I also reload with M118LR. I cut my match chamber at 1.631, which is a Bula barrel. After FTE issues, and some advice to get a RCBS mic gauge, I found out my lee dies weren’t cutting it for the chamber I had. I also had the same problem on a Springfield M1A. The lee dies were setting the headspace too long.
I purchased RCBS competition dies and have never had a problem. The RCBS mic gauge show that LC ball and my reloads are the same headspace.
I have both RCBS standard and Match dies. The cases used in these loads are LC unfired pulldown brass, run thru the standand die and trimmed in the Giraud . As mentioned previously, the cases them selves set in the chamber as they should, but loaded with the 168 Nosler, or even a 150 FMJ Hornady, will not sit as deep in the chamber. It has to be the throat. A 147 FMJ LC GI load sits in the chamber fine. Compare the bullet profiles and notice that the GI ball has maybe 1/8" of full diameter out of the case, where the other bullets have more full diameter forward of the case.
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  #10  
Old 07-10-2018, 02:35 PM
Deuceguy Deuceguy is offline
 
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i don’t use standard dies ever. Even for my as issue Garand.
Curious... when did u send this rifle to get fixed and when was it returned?
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