7 mm RRB

rick49 · Apr 27, 2015

attached are a couple of pics illustrating a near case failure in a RRB 1902 model 5.
The headspace checked out fine.
A member who reloads suggested I ask for opinions for options on what I might do short of taking up reloading for this one rifle and stop using modern ammo in this gun!

Thanks

Greenbug · Apr 27, 2015

Looks to me like that case that failed had been reloaded several times. Probably a little to warm of a load in your rifle, and the case head started to separate. Straighten out a paperclip then put a little bend in the end of it and run it into your cases. Feel for a line/ring around the inside of your cases near the head(end closest to the primer pocket). If you feel a ring on the inside of the case, then throw it away.

You don't always see a bright ring on the outside of the case when a case starts to separate, the paperclip allows you to feel inside the case for the beginning of case head separation.

Something leads me to think that this is probably not factory ammo, and that maybe someone sold it to you passing it off as such, but the markings on the case looks like it has been reloaded. Look at your live round in the picture next to the blown up one... see that ring near the case head? That marking is usually caused when you run the case through the sizing die. Just my two cents here but it looks like a reload. Sometimes you can tell if it is a reload by the color of the primer too. Silver colored primers are usually a reload, where as brass colored primers are generally a factory component (this is not a hard rule but generally a good indicator if you suspect that the cartridge might be a reload).

rick49 · Apr 27, 2015

checked the box(s) and all of them are silver primers. I have a box from a separate purchase and they are brass primers.

What can be done besides reloading to shoot this rifle.

Greenbug · Apr 27, 2015

Not sure what 7mm RRB is? Is it 7x57 mauser?

Reloading is not very difficult if you are willing to learn how to do it right. If it is 7x57 mauser you could get a lee load all for probably less than $40 and you would be in business less the primer/powder/bullets... I am still under the impression that you have reloaded ammo (silver primers like you say). That particular load might just be to "hot" for your rifle, or possibly over/under sized for your chamber creating a head space issue resulting in case failure. Have you fired more than the one round, did any of the ammo work fine? Or did the first round result in the case failure? You could try one of the brass colored primer rounds (most likely factory) and see what result you get....

What method/tools/gauges did you use to verify that the head space is correct on the rifle? I would be sure about the rifle's condition in that regard before I went any further...

Greenbug · Apr 27, 2015

If you could post a picture of the case head stamp of one or more of the cartridges that would help us know what cartridge we are dealing with here too! Kinda looks like a 7x57 mauser, but I dunno...

Greenbug · Apr 27, 2015

Just did some reading 7mm RRB (Remington Roling Block DUH!) chambered for 7x57 mauser.

It is a smokeless powder gun and should handle loads in the 40,000 PSI range with no problem. Commercially loaded factory ammo should shoot just fine in these rifles. However they were notorious for having "generous" chamber dimensions that caused problems with brass cases wearing out after only a couple of loadings. I would still have a gunsmith check out your rifle, if the head space is within specs you should be able to shoot factory 7x57 mauser ammo, and probably mil-surp 7x57 as well, so no need to reload.

If the ammo/brass you have had been shot and loaded a time or two that could be the cause of the case failure in your rifle.