help figuring out what went wrong. pics added

S

shooter444002

Private
Minuteman
Jan 24, 2011
24
0
49
#1
I have been reloading for 19 years and have never had a problem with over pressure, primers falling out or flattening and have always used and stayed within the book except on calibers I knew were a little under loaded like 257 roberts. But this blows my mind.

Got almost new 700 aac sd 308 yesterday, fired 3 factory hornady 168's through it, scope was on no problems. chambered a fed case, wlr primer, 45gr of varget and a 168 hornday loaded to same oal as factory ammo. pulled the trigger got slammed back, gas and brass hit me n the face and the floor plate was blown open! Bolt wouldnt even think of lifting. went back to the house pulled all loads and remeasured powder and bullet weight and everything was dead on the money. The case did have a little resistance when I chambered but not much. I measured cases which were once fired and they were a little long at the max length 2.015. The only thing I can figure is that it is tight throated and them being a little long was the culprit????

I beat the bolt open with a 2lb hammer!!! the front of the case looks fine but the base is melted into the bolt. Action and chamber look ok and I stuck another bolt in it and it functions fine with a dummy round, but I dont have a headspace gauge to check it for sure. Need new bolt and trip to the smith to make sure all is fine.

Anyone know where a bolt is??
 
#2
Re: help figuring out what went wrong.

Do you have any Pictures ... there was a thread a few weeks ago but he was using factory ammo and the ammo did not have a flash hole. But you are hand loading ... the only thing is could you have over charged the case?
 
#4
Re: help figuring out what went wrong.

powder was not mixed, straight out of can into clean rcbs chargemaster 1500. Bullets loaded to factory oal of 2.790 not out long. over charge of varget should have been a compressed load and this was not compressed, 1 gr less than hodgdon listed max for 168gr bthp. I pulled the bullets out of the remaining 9 loads and the powder charge was right on the money at 45gr out of every one of them.

Got scratching my head.
 
#5
Re: help figuring out what went wrong.

Tight neck. I think you answered your own question. Does the loaded round neck thickness equal or exceed the chamber? Can you drop a new bullet into the fired case neck? If not, you may not have enought neck clearance.

We need more specifics from you
 
#6
Re: help figuring out what went wrong.

Very weird to say the least ... The Gunsmith should have something to say-- something must have been wrong with the weapon, throat something ...Please keep us informed.
 
#8
Re: help figuring out what went wrong.

Did the projectile leave the barrel?

Is the barrel actually adequate to fit .308 or is it of a smaller size?

Please post up pics I would love to see what happened!... even tho I do feel for you
 
#9
Re: help figuring out what went wrong.

will get pics tomorrow, cant find the dang camera right now.

Yes the bullet left the barrel and hit within a inch of the aiming point. bore is correct at the muzzle.
 
#10
Re: help figuring out what went wrong.

shooter,

Not sure what your problem was. It could be the rifle, but here are a few thing to consider:

1) Hodgdon max load of Varget is 46 grains w/ a 168 gr Sierra SMK. You are using a Hornady 168 either A-Max or BTHP, not the same.

2) Hodgdon COAL for their max laod is 2.800. Yours was 2.790

3) Your cases were long.

4) Most importantly, unless you left something out, you were using a reload in a rifle you did not work up a load for. Because it was safe in another rifle, and under book max by 1 grain, means nothing.

New rifle, work up a new load.

Again it may be that the rifle was defective. Or, a combination of these factors:

Long brass
Different bullet than use by powder maker
Shorter OAL than powder maker
load developed in another rifle, and not worked up from below

I know in my 38 years of reloading: I've blown primers with a starting book load, in some rifles. I've also gone way over book
max in others. And never use a reload developed in one rifle, in a different rifle, even by the same maker. Threat every rifle as a new reload project, and work up from below.

Glad you were not hurt.

Bob
 
#11
Re: help figuring out what went wrong.

all true

was 168bthp

new bottle of powder too, newer lot, should have really paid attention when shot it in my sps before I fired the aac, because it seemed like their was more recoil.

also note to self and anybody else wear your glasses!!! brass buried up in the face and left marks on the lenses. You never know when something is going to go wrong, and it will probably be when you are most comfortable with something!!!!
 
#13
Re: help figuring out what went wrong.

Another possible culprit.
Do you have magnum primers around your bench?
A magnum primer could create too much initial pressure, forcing the bullet forward (plugging the barrel) before the powder could start burning. If the bullet was pushed into the lands, the pressure spike could be HUGE, pretty much the same as chambering a bullet that is too long.
 
#17
Re: help figuring out what went wrong.

DSCN0287.jpg


DSCN0286.jpg


DSCN0285.jpg
 
#19
Re: help figuring out what went wrong.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BobinNC</div><div class="ubbcode-body">shooter,


4) Most importantly, unless you left something out, you were using a reload in a rifle you did not work up a load for. Because it was safe in another rifle, and under book max by 1 grain, means nothing.

New rifle, work up a new load.



Glad you were not hurt.



</div></div>

Nuf Said.
 
#20
Re: help figuring out what went wrong.

Case mouth does not look pinched (as in at the front of the chamber, into the leade, leaving inadequate room for the bullet to clear.

BTDT 30 years ago with .30 Carbine, got lots of nice machine marks on the case walls and loosened a few primer pockets. But that round starts out at a 42 KPSI or so chamber pressure, not 55K. The long neck theory bears out some investigation.

Your fired cases taking a bullet in whole says NO case neck thickness problem.

But what brass was used? What's your fired case H2O capacity? I ask because MY brass, with Varget and 155-gr SMKs, turned out to be a little overpressure with 46.0 of Varget.

THEN there is the reported lot-to-lot variations in burn rate with Varget. It that still happening, perchance?

What I see back there by the bolt is what I would expect with an annealed dead-soft case head. Any chance that the empty brass got abused with heat while you weren't looking?
 
#22
Re: help figuring out what went wrong.

the brass was federal, it was factory hi shok softpoints fired in a rem 7400 about 8 years ago. I cant think of anytime the brass could have been subjected to heat as it was always stored in the house. I have several hundred pieces of mixed brass and sorted out these by weight and brand. Havent checked their capacity. they do seem soft though as you can chamber a case and when you pull it out the whole base is bright colored where it looks like the brass is just wiping off. I threw all the fed brass away!! Gonna order some new, got new bolt coming as well.
 
#23
Re: help figuring out what went wrong. pics added

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: shooter444002</div><div class="ubbcode-body">
Got almost new 700 aac sd 308 yesterday</div></div>

Guy I know had the same thing happen last month. The head space was completely screwed up. He had to go to the eye doctor and we're having to reschedule his PR I and II until his rifle gets out of the shop. His charge was at the low end of book data.
 
#24
Re: help figuring out what went wrong. pics added

I have noticed that the Hodgdon load data on their web page is hotter than the data at other sources.

I load the Nosler listed max of IMR4895 44.5/150 Accubonds or Ballistic Tips/.308Win in my R25, it is a good load for my rifle. The Hodgdon/IMR site gives 47.3 as a max load with my IMR 4895 load. I was shocked to see the difference.

Check other sources for the load and take the rifle to your smith.
 
#26
Re: help figuring out what went wrong. pics added

You dont have a 303 brittish do ya? The case head of that thing looks fatter that a 308 from the picture. I dont know if it would even fit, but you did say it was a little hard to chamber.
 
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