AI AX260 - Pierced Primer

N

NBot

Sergeant
Full Member
Minuteman
Apr 18, 2006
336
50
Minneapolis, MN
#1
Hey guys -

Question for you, anyone shooting a AX260 with a Bartlien barrel? I just picked up one recently and did some load development on it.

Virgin Lapua Brass -

@ 43.5 H4350 I was seeing extractor marks. Load ended up being 42.5gr H4350, BR2 @ 2.865" OAL. w/ 139 Scenars

Bug holes with this and flies at 2807


So, no evident pressure signs with this load

However, now I get to my second firing with the brass and now... 1 out of 5 I get a pierced primer. Bolt gets all jacked where you have to pull the bolt, disassemble and then you can have a working bolt again.

Brass was body sized, and neck sized with Redding Dies.

Anyone else have this problem?
 
#2
Re: AI AX260 - Pierced Primer

AI's piercing primers, especially on 260s is pretty common.

This is also a problem in AW rifles, although I have a 260 AI with a Bartlien barrel on it, and never pierced a primer.

I use the same 43.5gr of H4350 and have no issues. Are you loading it long ? I have them loaded very conservatively, are 2.810 -2.830 not much longer.

I forget if anyone ever found a solution, but it has been reported quite a bit.
 
#3
Re: AI AX260 - Pierced Primer

I'm loading 43.8 of H4350 behind Sierra 140 Matchkings, CCI-BR2 primers, Winchester 7mm-08 cases necked down to 6.5. 2.30 to the ogive, and I don't get any pressure signs at all out of a 27 inch Obermeyer 5R barrel with a comp on the end.

When I was working up the loads, I was able to go another 1.5 grains or so, still without any significant pressure signs. Bolt opened easily, no extractor or bolt scuffs, no primer squash. I stayed at 43.8 because that was where the best accuracy was. Velocity is around 2900 fps (2870 IIRC), and the rifle shoots as far as I need it to.

I guess that is a long way of saying I doubt it is your load causing the primer piercing. DPMS had difficulty with primers in the development of their 260/6.5 Creedmoor rifles, so I think it is something particular to the 6.5 bore cartridges having a capacity similar to the 308 case.
 
#5
Re: AI AX260 - Pierced Primer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">I forget if anyone ever found a solution, but it has been reported quite a bit. </div></div>A firing-pin hole bushing.
 
#6
Re: AI AX260 - Pierced Primer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Graham</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">I forget if anyone ever found a solution, but it has been reported quite a bit. </div></div>A firing-pin hole bushing.</div></div>

Dang... Really? I'd hate to do it on my brand new bolt.
 
#7
Re: AI AX260 - Pierced Primer

My surgeon 260 pierced a primer a lil while back. Took it to GAP and they put new trigger in it. Shot it that weekend and it shot great, put it in the case and drove home, got home and now it doesn't fire at all. Seems like the spring is super weak and it barely dents the primers. The load is not hot at all. IS this kindof the same thing? Not trying to hijack. just wondering. Good luck with your rifle
 
#8
Re: AI AX260 - Pierced Primer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Graham</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">I forget if anyone ever found a solution, but it has been reported quite a bit. </div></div>A firing-pin hole bushing.</div></div>


Well.. I heard back from Tannel. He doesn't do bushing for AI's. Anyone know who does this? Also, where I can buy a new bolt?
smirk.gif
 
#11
Re: AI AX260 - Pierced Primer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: attherange</div><div class="ubbcode-body">what brand of primers are you using??</div></div>

CCI - BR2
 
#14
Re: AI AX260 - Pierced Primer

My AW 260 with a Bartlein barrel had accuracy nodes at 43.5 and 42 H4350, 139 scenar, 2.8 coal, new lapua brass. (edit: fed 210 primers)

At 43.5 had a few pierced primers, pressure signs otherwise and primer pockets were well on their way to being trashed.

I reduced the standard load for the gun to the 42grain node with no loss in accuracy at distance and no pressure signs.

Good luck!
 
#16
Re: AI AX260 - Pierced Primer

I am running an AI AW with GAP .260 Bartlein barrel. I use Lapua brass, 42.6 grain H4350, CCI BR2 primers, and 139 gr Scenar. I am getting 2850 fps with no pressure signs and I have never pieced a primer in about 1000 rounds. You might want to contact AINA to see if they can help.
 
#17
Re: AI AX260 - Pierced Primer

Well my gun isn't exactly and AI but it's Badger M2008 action/copy of the AI type action.

I've got two barrels fitted up. A .260 Rem. and a .308 win. Never pierced a primer on either barrel.

The hottest load I've run with the .260rem. and 139/140gr. bullets has been 43.0 of H4350. Out of a 24" finish length barrel the bullets where going like 2830fps.

Primers I've used have been both the CCI BR and Fed210M's.

I've been using Rem. brass and just got some Nosler brass. Rem. brass is on 3rd reloading. Haven't shot up the first loading of Nosler brass.

The Nosler brass was around 5gr. heavier than the Rem. brass but haven't had any problems.

As the suggestion was made I would contact AI/Dave Tooley and see if they can help etc....

Later, Frank
Bartlein Barrels
 
#18
Re: AI AX260 - Pierced Primer

I'm running an AIAE MKIII with .260 AINA Bartlein barrel. Before I ran an OCW, I ran a pressure/velocity test. I hit 44.5 grains of H4350 in a Lapua case, with BR-2 primer and 142 SMK @ 2.850"ish OAL. The 44.5 gr H4350 gave me 2,875 fps @ 2,000' DA. No pressure signs at all, but I'll double check my notes when I get home.

I'm currently running:
142 SMK
43.4 gr H4350
Lapua brass
CCI BR-2 primer
2.895" OAL
2,825 fps

I haven't seen the slightest pressure signs of my current load, and I've ran it in 95* temps.
 
#19
Re: AI AX260 - Pierced Primer

Are you guys bumping your shoulders? Or are you full length sizing?

The only thing I can think of that would be different is I am bumping the shoulders.

Virgin brass = no pressure

Non Virgin = Issues. LOL
smile.gif
 
#20
Re: AI AX260 - Pierced Primer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: NBot.MN</div><div class="ubbcode-body">Are you guys bumping your shoulders? Or are you full length sizing?

The only thing I can think of that would be different is I am bumping the shoulders.

Virgin brass = no pressure

Non Virgin = Issues. LOL
smile.gif


</div></div>
I ran my pressure/velocity test with new, prepped brass. I bump my shoulders 0.001" with a Redding FL Type S Bushing die and a TiN bushing for 0.002" neck tension.
 
#22
Re: AI AX260 - Pierced Primer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: deisel</div><div class="ubbcode-body">I use a Redding FL die on my brass, I bump the shoulder back .002. I also jump the bullet .002 from the lands. To the original poster are you jamming the bullet into the lands? That can certainly increase pressure. Just a thought.</div></div>

Not jamming the bullet.

I think I am going to try RL-17.
 
#24
Re: AI AX260 - Pierced Primer

I think you are bumping the shoulders back too much. Try just neck sizing and see what happens. I did this on my 204ruger and I was blowing primers out with the same load. Come to find out I bumped the shoulders back too much(excessive headspace). Let us now how you are making out. I have 2 260s and I have shot 43gn under 142gn bullet without a problem in my 28" and in my 19" I am puttin 43.5gns under the 140s and still could put a bit more.

I am curious to see how goes the battle.
 
#25
Re: AI AX260 - Pierced Primer

Any chance your chamber, or your cartridges themselves, are in any way lubricated?

A buddy pulled his rifle out of storage and forgot to de-oil it, and was blowing primers with 175gr FGMM. Eliminating the lube solved it.

Just a thought.
 
#26
AIAE MKIII with .260 Kriger barrel

COL 2.840 <- to long?

load tests today, mild loads, 42.3,42.5, 42.8, 43 h4350 140 amax
if you look at the edge of the primers you see they are nice and round..
yet the pin hit is popping up and out...

im going to try COL 2.800 next to see if it helps

also, on a wilson case gauge, a fired case is measuring .006, my savage and Rem-Age700 are normally .002 for head space

 
Last edited:
#27
So after 300 rounds my AIAW with a .260 Bartlein started blowing primers. At first I saw some of the cratered primers that Ring has pictured not quite understanding what was about to happen.

I'm shooting CCI 200 primers, Lapua Brass, 43.2gr H4350 with 139 Scenars. I am .030 off the lands. The loads chrono at 2800 fps but when I true up my ballistic table it says I'm getting more like 2850. 43.2 was also my OCW load. They are blowing with virgin brass.

I spoke to the folks at Mile High Shooting center (where I got my rifle and barrel - great folks BTW) and they told me it's copper buildup and I need to remove it with something like Montana Extreme or Sweets 7.62. I'll give it a shot and see what happens.

I'm really hoping to resolve this problem as my .260 is extremely accurate. I'm also impressed that my AIAW didn't suffer any damage - I just had to take apart the bolt as the bits of primer cup were blocking the firing pin.
 
Last edited:
#29
Ring said:
I was told the same ... I had zero copper, I know this because I got the gun with 380 rounds down it..

When I got it I foamed it... Kg12"Ed it, then JB polished it...
I fully stripped it ... After that, I Applied Dyna bore coat
DYNA-TEK Bore Coat Article

And was using HBN coated bullets...

Sent from my Nexus 4 using Tapatalk
Click to expand...

Any improvement after all that work? Are you still blowing primers?

I don't hear of anybody piercing primers with the .308 and they are running some hot loads.
 
#31
I cleaned my barrel with Sweet's 7.62 - the strongest stuff I had sitting around. I didn't get any copper at all - nada...zilch. At least I got all the carbon out. I'll shoot tomorrow and see how I do.

If I continue to get pierced primers I will work up a load at a lower accuracy node. I'm not to happy at the prospect of doing that since I'm giving up a lot of performance associated with the .260, but it will still be better than the .308.
 
#32
Hi,

Since my earlier post I even used some Butch's Bore Shine and ran a phosphor bronze brush up and down my bore approx 60 times. I did get some carbon but no blue to indicate copper.

I fired about 15 shots and I got a pierced primer. I am now going to start loading one accuracy node lower (42gr. H4350)

One of my next major purchases will be a bore scope.
 
Last edited:
#34
It's not so much copper deposits as a carbon ring just in front of the chamber...

Some people claim certain powders like H4350 have an excessive build up, hence you have the carbon ring which causes the pressure issues people are talking about. It's not copper though, same effective different culprit. Which is why you got no signs of copper fouling.
 
#35
Lowlight said:
It's not so much copper deposits as a carbon ring just in front of the chamber...

Some people claim certain powders like H4350 have an excessive build up, hence you have the carbon ring which causes the pressure issues people are talking about. It's not copper though, same effective different culprit. Which is why you got no signs of copper fouling.
Click to expand...

Frank,

Will your cleaning technique that you demonstrated in the Online Training forum address this? Or is more aggressive treatment required?
 
#36
Known said:
Fired 40 rounds with 42gr H4350 and no pierced primers. I did get one cratered primer which makes me nervous.
Click to expand...

And sure enough I got a pierced primer after 125 rounds. I'm going to try Zak Smith's recommended load of 40.7gr H4350. He claims to get 2800 fps from this load from a 26" barrel. He must have a faster barrel than me.

EDIT: Come to think of it, there is a comedic angle to the whole thing:

My .260 reloads are so slow now

Audience: How slow are they?

They are so slow, I can walk to my target and wait for the bullets to arrive
 
Last edited:
#37
Known said:
Frank,

Will your cleaning technique that you demonstrated in the Online Training forum address this? Or is more aggressive treatment required?
Click to expand...

you may just have to clean it after 100 rounds, clearly the rifle is speaking to you. So try cleaning it every 100 and see what happens. It's might smooth out, go on cleaning every 100 for 500 rounds then shoot it again without and see what happens.
 
#38
OK - the 40.7gr load did not pierce primers but I got some minor cratering. Temps were 40F so I'm concerned what might happen during the summer. I didn't chronograph the loads, but when I true up my ballistics I'm around 2,670 fps with 139 scenars. AI offered to inspect my barrel if I send it in so that's what I'm going to do along with some of my fired brass. For now I'll spin on my .308 barrel.
 
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