Case Head Exits Rifle

[Jim Tarleton]

You guys did should a good job on my last poblem, I thought I might share an experience that I still don't understand. My first "big bore" rifle was a 7mm Rem Rolling Block. I didn't like it and I sold it. A few years ago I bought two 7mm RRB's to play with. I made one into a hunter ala de Haas. I fit the barrel to the receiver with essentially zero clearance between case head and block. No headspace problem at all (finish reamed it myself). I buy two boxes of 7mm commercial ammo. No problems, good accuracy. When I reloaded these cases, I noticed a lot of case stretch. Had to full length resize and trim more than normal for a single firing. Out come the GO/NO_GO's. No headspace problem with very minimal headspace. Trimmed the once fired cases and loaded them up.

Ist handload, which was relatively mild, the case head blows off and hits me in the forehead right above my left eye so hard I was stunned - cut to the skull, blood everywhere - wife freaking out. I thought the RRB had blown up. Nope. It was in fine shape with minimal headspace. I put the rifle in the safe and left it for a year. Recently I pulled it out, and tried handloads again. Every reloaded case parts or begins to part, but none have exited the rifle has did the first one. I can only use new brass in this rifle.

The loads are 3 grs from published max, so pressure is not the problem. My question is: How did that case head come out of the block? A 0.001" feeler gauge won't slide between the case head and the block and there are no signs of excessive pressure whatsoever.

My question for those familiar with RRB is how did that case head exit that receiver block without damaging the receiver? I thought the RRB's were case hardened. A RRB locks up tight as a drum.

My take is that only new brass can be used once, as the case stretches so much that a second loading results in a separated case head. How can there be that much spring in a case hardened rifle reciever? The case head that hit me fell into my shirt pocket after it hit me in the head and it is about 1/4" long. The remaining case easily came out with a tap with no sticking evident.

Any ideas? I have pondered this for two years, and I find it very suspicious.

Jim.

Information

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[snakehunter]

I had exactly the same problem with mine, except it happened with new, factory loaded ammo. I alway's assumed it was headspace.

[MEHavey]

Are you saying the action opens and the case head separates? (Or equally bad, the case separates and the action opens?)

For what it's worth, fire a resized/primed-only case and tell us if/how much the primer backs out.

[Jim Tarleton]

A fired primer is flush with case head, which was what I expected. Believe me, headspace isn't the problem.

I don't know what happened other than the case head hit me in the head above my left eye. If you are familiar with Remington Rolling Blocks, once the trigger is pulled and the hammer falls, it is a tight lockup. The hammer is firmly beneath the block, all held together by the pins through the hammer and block. I am puzzled as to how something that large exited between the barrel and the block, when there is essentially zero space between the block and the case head, which is flush with the breech end of the barrel.

The action did not open, and can't unless the hammer is pulled to the rear. It had the appearance of a locked breech with smoke coming out of the cracks. With few exceptions, every reload separates just in front of the case head, presumably due to stretch.

I use a vernier sight mounted on the receiver buttstock rails, which places my eye in a rearward position. I suspect that sight saved my eye.

Sounds like someone else had the same experience. If headspace was the problem, I still don't understand how the case head could come out of the locked breech. If you examine a Remington Rolling Block, I think you will see what I mean.

Jim

[joem]

I didn't see you reload data. I shoot a very old RRB (1882) and reload all my ammo.

[joem]

I didn't see you reload data. I shoot a very old RRB (1882) and reload all my ammo.

[Jim Tarleton]

I am at work, I will get it for you tonight.

Jim

[Jim Tarleton]

I didn't see you reload data. I shoot a very old RRB (1882) and reload all my ammo.

By the way, this is a 1902 7mm RRB (smokeless), just for your info. I do have a Huskavarna (what are the odds of spelling that correctly?), but I have never barrelled it.

This was going to be my swamp rifle. I will post a picture of it tonight. I went rather mild on the load, or thought I did. Evidently not mild enough, although factory 7x57 rounds work fine with no problems.

Jim

[slamfire1]

I don't know what happened other than the case head hit me in the head above my left eye. If you are familiar with Remington Rolling Blocks, once the trigger is pulled and the hammer falls, it is a tight lockup. The hammer is firmly beneath the block, all held together by the pins through the hammer and block. I am puzzled as to how something that large exited between the barrel and the block, when there is essentially zero space between the block and the case head, which is flush with the breech end of the barrel.

After reading your description, it is my considered opinion that your RRB, and maybe all RRB's are very springy actions. Something is stretching under load.

The original RRB were made for blackpowder, probably made of mallable iron. While the lock up appears tight, that does not mean that the action does not stretch when loaded. Cases developing stretch marks are a dead giveaway that the action is stretching.

While the blocks are large, the load path is through the screws that hold the breech block and the trigger to the receiver. I will bet that those are a mild steel, if that, and the receiver is probably case hardened soft steel.

Cut your loads way down. Heck, use cast bullets, what way you won't be tempted to soup the thing up.

I found your post interesting as it shows that the RRB action does not protect the shooter as well as some other single actions. I suspect a Highwall, Martini Henry, would have protected you better than the rolling block.

[MEHavey]

...fired primer is flush with case head, which was what I expected. Believe me, headspace isn't the problem.

1) But did you fire the primer without a powder charge/bullet -- just empty case?

2) When the case head hit you in the forehead -- but the action was still closed -- did you mean just a piece of the rim?



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