AR failures

[biglou13]

no name upper with m4 ramps

ballistic advantage barrel 16 inch hanson profile.223 wylde

rubber city gas key

tac-com rifle alw buffer/system

enhanced spring

mil spec no name bolt/bcg

xbr powder

55grain

dillon case gauge

less than 30 rounds through barrel

i started tuning a new AR (ish)/m4gery.

forward bolt movement is tuned properly

gas key is tuned properly

failures:

i had a few difficult to extract loaded cartridge

had a few failure to return to battery

FTRB:

The FTRB were with one specific magazine and only when loaded with approx 5 rounds or less

NO FTRB with 20 round mil spec mag

NO FTRB with full mag

at this point I'm writing this off to mag failure

will retest with another brand magazine

never had issues with stock pmags and mils spec al mags

difficult extraction:

shot cases were extracting fine, bolt cycles fine

only had difficulty in extracting occasional loaded rounds, from FTRB's

and manually cycling bolt with loaded cartridge

if i recall i believe these were with same "problem" mag

i literally needed to pull charging handle with both hands to extract

please advise?

RO suggests dirty chamber, due to dirty powder.

i'm thinking cursed magazine

I'm also thinking new barrel/bolt needs break in....

is XBR considered a "dirty" powder?

any ideas or suggestions

and i'm sure some of this is may be break in issues.

i understand and accept that "upgrades" can decrease reliability

Edited July 19, 2016 by biglou13

[Dan Sierpina]

Were the loads on the light side? 8208 is a slower powder than say H335. It would probably work better with hot loads and / or heavy bullets.

Was the brass sized sufficiently? Just because it fits the gage, it may still be tight in your chamber. I've experienced this with .308.

How wet did you run the gun?

[biglou13]

Lake city. 1x, I bought the brass swaged sized trimmed and clean I ran some though all Lee dies on Dillon 550. No fcd / 4th. Some just loaded as bought. Empty case legnth is fine, And empty cases case gauge fine also. I don't have shoulder comparator device yet. My load is on lower end of book. I'll get back to you with load. Dillon case gauge. I do have a Wilson is that one tighter?

If it's a loading issue I'm willing to make changes.

It was damp. Not wet..... But I'm rethinking running wet. I did add some oil over previous slide glide and oil.

I'm going to give it another solid cleaning before next test.

[sschultz]

Go buy a box of factory loads and try them.

[RJH]

I am going with ammo issues not gun issues, and second the suggestion to buy some factory new (not factory reloads) ammo.

[bwikel]

Sounds like an ammo issue not a gun issue. Are you sure you have your shoulder bumped back far enough when you are sizing the brass? It is possible for it to pass the Dillon case gage and not have your shoulder set back completely which would cause a failure of the rounds to go fully into battery and be very hard to extract un-shot rounds from the chamber. Your sizing die may need another 1/4 to 1/2 turn down so the press cams over at the end of the stroke.

Edited July 20, 2016 by bwikel

[dillon]

For use in a semi-automatic rifle, a sized, lube-free case should drop in flush with the lower step on a Dillon Precision headspace gage. The lower step is minimum headspace. A factory round should drop in that far as well.

What you described sounds like the size die is not pushing the case shoulder down to the minimum specification. It may be necessary to turn the die down an additional 1/4-1/2 turn beyond the point where the bottom of the die contacts the top of the shellplate. Rely on the gage to tell you when the size die is correctly adjusted.

[Kaldor]

Go buy a box of factory loads and try them.

My thoughts as well. I test every new build with 5-10 rounds of factory ammo.

[biglou13]

Bwi... And Dillon....

Please clarify. Dillon case gauge does or, does not measure shoulder bump?

videos and Dillon says it does measure shoulder bump.????

If not what points does it gauge?

I have a case comparator to measure shoulder bump/ datum line en route.

I'm too trusting thinking that my brass was previously prepped appropriately.

Edited July 21, 2016 by biglou13

[Steve RA]

The brass could be OK and your chamber on the short end of the specification range.

[dauntedfuture]

Your not FL sizing the brass enough. This is different from bumping the shoulder. If loaded rounds are sticking in the chamber then you need more size die. You also need to check several FL sized cases when you use range pick up brass and make sure they all work. Many times you will get a few in the pile that are way out of whack with the shoulder blown well forward and you would not catch these cases.

Believe it or not, you can often neck size 5.56 and get your rifle to run well some of the time; it just so happens that your sizing the case as your bolt slams it home. Im not suggesting this, but it can be done. When your FL die is not set up right, your just sizing the neck and the sides of the case and possibly not touching the shoulder

[bwikel]

If you set your press up to cam over slightly at the end of the stroke it should cure your problems. Your chamber is probably tighter than the gage you are using.

Edited July 21, 2016 by bwikel

[biglou13]

Thanks all great advice...

m going to revisit an review re measure my reloading process.....

Thing is every loaded cartridge passed case gauge ..... I'll recheck remaining rounds from that batch with dial gauge with case gauge

Is ballistic advantage Hanson barrel known for a tight chamber?

[bigedp51]

A Wilson and Dillon .223 case gauge will only check the shoulder to base measurement and not case diameter.

A JP Enterprize case gauge is made from a chamber reamer and does check case diameter.

When I buy once fired Lake City 5.56 brass it is sized the first time in a RCBS AR Series small base die. If the once fired Lake City brass was fired in a SAW machine gun its chamber diameter can be .003 to .004 larger in diameter than a .223 chamber.

What you might be dealing with is brass spring back after sizing and the case diameter may be causing the problem. I size the Lake city brass the first time with a small base die and I also pause at the top of the ram stroke for a few seconds. This reduces brass spring back from the chamber dimensions the case was fired in the first time.

My RCBS .223/5.56 small base die only sizes the case diameter .0005 smaller than my standard RCBS die does.

We live in a plus and minus manufacturing world and no two chambers and dies are exactly the same. Meaning you could have a chamber on the minimum side and a die on the plus side and brass spring back causing the problem.

Edited July 22, 2016 by bigedp51

[biglou13]

Good info biged....

So how an you tell if it's the case diameter vs shoulder causing issue?

I have a Wilson and Dillon .233 case gauge.....

I'm interested in jp gauge. I always assumed case gauges were cut by reamers.... And red is cool too.

I discovered my mistake!!!

I used a dial mic stand and measured. Yes you guys were right. Some were .0005 to .0015 too long

Cheaper version of dial indicator stand. http://www.midwayusa.com/product/310955/rcbs-case-master-concentricity-gaging-tool

Mistake one

Trusting others to prep your brass. I bought brass cleaned sized de primed swaged, trimmed, chamfered, deburred ... I measured a handful which spec'd fine. Did'n't measure more. I did not resize when loading assuming all is within spec. I'm now checking brass prior to reloading

Second mistake

is to use case gauge in poor light, with ailing aging eyes..... I used to be able to see .+001.

As of today I have become a "scraper" (scrape top of case gauge with straight edge) I will always wear my " cheaters".

Edited July 24, 2016 by biglou13

[biglou13]

Now I want a jp case gauge....

I got to try Dillon and Wilson gauges side by side

The Wilson is a bit tighter