BA13 case head separation

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15-09-2021, 09:14 PM
ebf

BA13 case head separation

Was up at the local range doing some testing, and had a run of case head separations in my Bergara BA-13 308.

Now I will be the first to admit that the brass was getting on in years, and had been used for several fullbore seasons.

When I got back home, I measured the fireformed shoulder length, and noticed that it was sitting around 1.630.

My 308 body die was set to push the shoulder back to 1.622, so obviously did not help matters.

Now for the weird bit... after thinking about it some more, I got out my go/no-go gauges. they measure 1.630 and 1.634. The BA-13 closes on both...

Curious to hear if anyone else noticed a particularly "long" chamber in the Bergara.
15-09-2021, 10:29 PM
Micky Duck

my old 270 would just close on no-go guage if the fireing pin was removed....what I did was partial length resize from then onwards and was anul about use of paper clip feeler guage.30 years and never an issue again.....
it was a case seperatio on 2nd firing that made me try guages.
16-09-2021, 07:37 AM
Marty Henry

Had the cases been fired in that rifle previously if so they would have grown to fit the chamber surely.
16-09-2021, 02:17 PM
shooternz

My B13 is a .44 mag so no problem, Just take it up a notch recharger to 30/06 or something no one else has
a 7.5x55 Swiss I know where a chamber reamer is.
16-09-2021, 02:25 PM
Marty Henry

Or 7.5 MAS
16-09-2021, 03:12 PM
grandpamac

Greetings ebf,
I have a BA13 in .308 and have had no problems in spite of using fairly elderly cases. I keep my loads quite low as the rifle is a packable takedown for trips where the primary activity is not hunting. It seems from your description that you have set the shoulder back too far and the elderly brass has finished the job. There also seems to be a disconnect between your measured fired brass length and the no go gauge. The BA13 is a quite springy action due to its break open type, quite safe with factory loads but hot handloads or dodgy brass not so much.
Regards Grandpamac.
16-09-2021, 03:49 PM
ebf

Quote:

Originally Posted by grandpamac

Greetings ebf,
I have a BA13 in .308 and have had no problems in spite of using fairly elderly cases. I keep my loads quite low as the rifle is a packable takedown for trips where the primary activity is not hunting. It seems from your description that you have set the shoulder back too far and the elderly brass has finished the job. There also seems to be a disconnect between your measured fired brass length and the no go gauge. The BA13 is a quite springy action due to its break open type, quite safe with factory loads but hot handloads or dodgy brass not so much.
Regards Grandpamac.

Yeah, I wondered about that. Using the hornady headspace gauge (0.400) that I did the fireformed cases with, I get 1.620 and 1.624 when measuring the gauges.

I got some once fired Federal brass from a friend last night. That measured 1.626, so will load a couple of those and see how they go (with body die adjusted correctly this time, haha).
16-09-2021, 05:55 PM
veitnamcam

The rifle probably has generous headspace by design to ensure it will close and lock properly on most ammo.

The discrepancy between the fired case and the gauge may be it had a long way to stretch and sprang back.....a couple more fireings may push it out fully to chamber size.
16-09-2021, 06:34 PM
Stocky

I'm guessing either you got unlucky as I ran some pretty warm loads in mine (225 eld m loaded very long at 2450fps in Lapua Palma brass and never had an issue. I did here that the action could stretch (I did check barrel to frame gap with shims and it never changed running probably 100 rounds of that load before I decided I would stick with factory ammo for ease. Does seem odd though that both the go and no go gauges fit. There much resistance closing the action on the no go gauge. I'm sure a gunsmith will pipe in with an abvious answer.
16-09-2021, 07:02 PM
ebf

Just to be clear, the separation I am pretty sure was just the result of old brass and pushing the shoulder too far back. That is easily solved.

The question about long chamber was more about if break-open design inherently gets done with a longer chamber, for some of the reasons already mentioned...
16-09-2021, 07:06 PM
Stocky

I wouldn't think so I thought they still headspaced the same I remember seeing a good diagram on here or maybe the other forun years ago in a thread about rebarrel lying a Thompson break action.
16-09-2021, 10:05 PM
Micky Duck

Quote:

Originally Posted by ebf

Just to be clear, the separation I am pretty sure was just the result of old brass and pushing the shoulder too far back. That is easily solved.

The question about long chamber was more about if break-open design inherently gets done with a longer chamber, for some of the reasons already mentioned...

my Brother said his rossi .308 is waaay long in the lead dept...I suggested it COULD be to accomidate the 7.62 rounds specs....longer leade to reduce pressure.
maybe generous dimentions are also a thing for singles.
17-09-2021, 08:03 AM
Marty Henry

"Flanged" cases in break action rifles would surely be the best option, headspaced on the rim.
I have seen a baikal 7.62 x39 rechambered to .303 which got me all excited for a while 7.62x54 r would also be a good candidate. I realise this is off track but I think it's worth mentioning if someone is looking for a project.