How to blowup your rifle

[105amatt]

Same here. I've shot Noslers and Bergers in the same range trip multiple, multiple times with no issue. Interesting about the mentioned pressure spike in ultra cold conditions.

 

[Trnelson]

In my 264 WM Retumbo has exhibited massive pressure spikes in cold weather with the same load that was safe in warmer( non-freezing) temps.

I have experienced the same issue in a 264win and also in a 30/338win. I switched powder away from retumbo and have not had anything similar happen again.

 

[Scooterbum]

U might wanna scope the barrel, looking for anamolies.

 

[Barrelnut]

I read that it may be possible to get hangfires in extreme cold like this. This may explain why so much pressure out of the blue and the 230 being so much faster than the 190. It may have been a very slight hangfire and possibly related to Retumbo (as the pattern seems to indicate). It may not happen with every round even. Could be the powder stuck to the front of the case or a small space in the powder column due to the extreme cold.

Might not take much to have the primer not ignite the powder uniformly in extreme cold with a bulky slow powder like Retumbo. Would be interesting to talk to Hodgdon about it.

 

[bigngreen]

I've seen more than once extreme pressure spikes, extreme velocity, and Berger's blowing up at the muzzle when following Accubonds, the barrels have all shown extreme copper fouling but after significant cleaning they shot the same loads perfectly fine just always cleaned between bullets. Seems to show up in the mid life of a barrel.
Bullet alloys vary and some get sticky with each other, you'll can find more on this, many have ran into it and won't mix jacket types.

 

[stillkickin]

Wow, thanks for posting. Might have saved someone from serious injury or worse. Hopefully someone will figure out what happened.

 

[Barrelnut]

I've seen more than once extreme pressure spikes, extreme velocity, and Berger's blowing up at the muzzle when following Accubonds, the barrels have all shown extreme copper fouling but after significant cleaning they shot the same loads perfectly fine just always cleaned between bullets. Seems to show up in the mid life of a barrel.
Bullet alloys vary and some get sticky with each other, you'll can find more on this, many have ran into it and won't mix jacket types.

I do know that changing bullets from one brand to another does affect velocity for 5 or 6 rounds, until it seems the original copper/powder layer gets kinda blown outta the muzzle or something. You will get erratic velocity and accuracy issues. I really try to avoid shooting one bullet type after another without a good cleaning first. Of course I have never done this in -10 degree temps though!

 

[J E Custom]

You don't follow Accubonds with Berger's, the copper fowling is not compatible between the two brands, I've seen this before!!
I guess I don't understand why the smith didn't simply remove the barrel, usually just remove the barrel and everything comes apart, Tig the bolt handle back on or replace the bolt and move on.

That was my thought. I would have unscrewed the barrel from the action and I also never recommend beating on any bolt if it is stuck. If you release the pressure on the bolt you can save the action. The barrel may have been ok also.

Look at your loading notes and see if you used the same powder and charge for the 190s and the 230 grain bullets If so that Is probably where you went wrong, especially using Retumbo. In my experience, I have found Retumbo to be one of those powders that can go critical with just a slight change in charge weight or bullet weight. Most powders are very linear and slight increases will give you slight increases in velocities. there are a few more that exhibit this trait .

For future information, if anyone has a problem with a stuck bolt, or any other situation, Please call a smith or post on this web site that you could use some help and advice how to fix your problem. there is a lot of knowledge on this site and plenty of people that should be able to help you out. It could save your rifle. I have removed barrels for many reasons and many different ways to save the action and with a little inspection and test found the action sound.

J E CUSTOM

 

[Winkfish]

Would anyone be interested in looking at the barrel to see what their thoughts are? I would be happy to ship it to someone who may be able to provide some insight

 

[AZShooter]

Terrible day for your rifle but you escaped injury.

Any chance that you had a powder bridging issue? Failed to fill one case with some powder left in funnel then next charge over filled the next case? You may discover this was the problem when you pull all the other 230 gr loads.

What scale are you using? If it is an old balance scale any chance one of the sliding pieces got bumped?

 

[jimbires]

I plugged his info in quickload .the 300RUM is rated at 64977 PSI . 89.7 grain retumbo looks to be a max load at 64944 PSI , with the 230 berger .

his 86.8gr has a case fill of 97% and has 58055 PSI 2762fps with a 26inch bbl . it's a mild load .

it takes 100.0 grain of retumbo to get 3121 FPS at 112% case fill , this generates 96625PSI .

91.5 gr ( his 190 load with a 230 bullet ) is 69613 PSI , 102.6% case fill , 2892 FPS .

what I'm getting at is ;
I don't think the 91.5 gr powder with the 230 gr bullet would cause this . it's only about 5000 PSI over max .

he should have noticed the increase in the case fill 97% vs 112% when seating the bullet . if some how he did get 100 gr of powder in the case .

97% is full enough to not be worried about powder position in the case causing a hang fire .

 

[Lrt307]

I plugged his info in quickload .the 300RUM is rated at 64977 PSI . 89.7 grain retumbo looks to be a max load at 64944 PSI , with the 230 berger .

his 86.8gr has a case fill of 97% and has 58055 PSI 2762fps with a 26inch bbl . it's a mild load .

it takes 100.0 grain of retumbo to get 3121 FPS at 112% case fill , this generates 96625PSI .

91.5 gr ( his 190 load with a 230 bullet ) is 69613 PSI , 102.6% case fill , 2892 FPS .

what I'm getting at is ;
I don't think the 91.5 gr powder with the 230 gr bullet would cause this . it's only about 5000 PSI over max .

he should have noticed the increase in the case fill 97% vs 112% when seating the bullet . if some how he did get 100 gr of powder in the case .

97% is full enough to not be worried about powder position in the case causing a hang fire .

I agree that the 91.5 charge doesnt seem to me that it would cause this by itself. I have run 93 grains Retumbo with the 230 @ 3075fps. I am wondering if there would be any possibility on barrel constriction in the -10 temps? How long did it sit before it was fired again? I have also found that my 71 grain retumbo charge in my 7mm is perfect from 10°f all the way to 80° and up. If I shoot this load below 10°f like around 0°f it shows high psi!

 

[bigngreen]

Retumbo is one of my go to powders and I run it hard in WSMs and RUMs and I shoot all the time in the -20 to 60 degree range and never seen an issue. It is a dirtier powder than say H1000 and watching fowling is more critical but normal cleaning practices tells a guy where he needs to be.
I would gladly take it apart and borescoped the barrel and see if it may have a bore related issue!!

 

[codyadams]

Good knowledge. I had heard about the different jacket issues following each other, but it was just a theory. Hearing it from J E and other knowledgeable shooters is good. I would always clean between bullet switches anyway, but this gives even more reason to do so.