RELOADING FOR THE 7X57 ROLLING BLOCK

[Doug Bowser]

RELOADING FOR THE 7X57 ROLLING BLOCK

Attachment 77020

I have been looking for this photo in my firearms files. The Model 1901/02 Remington Rolling Block was made for higher pressure rifle ammunition than the earlier 1868 and 1879 rifles. Off the top of my head, these were the modern smokeless powder calibers offered by the factories that made the rifles:
1. 7x57 Mauser (Remington)
2. 8x58R Danish (Husqvarna)
3. 8x50R Lebel (Remington)
4. .30-40 Krag (Remington)
It is not that the rifle is weak but most single shot rifles do not handle escaping gas (from a burst Ctg) very well. The photo shows a 1901/02 Model in 7x57 Mauser. I had a report with the photo, that the rifle was being fired with a load suitable for the 1898 Mauser rifle. That is a load too hot for the 1901/02 rifle. Another problem with the 7x57mm 1901/02 rifle is, the headspace in the rifle is usually .008"-.010" longer than the standard SAAMI chamber. These rifles will usually eat a 7x57 Mauser field gauge. These rifles were made long before SAAMI was in existence. The result was a full case head separation and the hot load blew the rifle up. The shooter was injured and as you see the rifle was really wrecked.
I would not fire factory ammo in a Model 1901/02 Remington in 7x57mm. It should be reloads only. To fix the headspace, the easiest thing to do is alter the ammunition. The procedure is, expand the neck of a 7x57 ctg. with a tapered .30 or .32 neck expander (LEE). The case has to be full length resized but back out the die so the headspace on the small area of shoulder is long enough, that the breech block will barely close on the case. Lock the lock ring on the FL resizer. Size your neck expanded cases and load a normal load in them. I would keep 1901/02 loads down to 40,000 psi. Fire form the cases and the shoulder on the fired cases will fill the shoulder area.. Keep the Rolling Block ammo separate from standard 7x57 ammo.
If you don't have a ready supply of 7x57 cases, you may have a quantity of 8x57 Mauser cases. Run the 8x57mm cases through the full length sizer and trim to minimum length. Be sure you don't have any case sizing lube in front of the shoulder, it will dent the shoulder area badly because you will be moving the shoulder back toward the head of the case.
There is a danger in this procedure. When sizing a neck down to a smaller caliber, the outside loaded diameter of the neck must be smaller than maximum, the dimensions given for the neck diameter in our reloading manuals. It is really better to be .001" to .002" smaller than maximum in loaded neck diameter. The problem with the necks being over sized is, the bullet might be squeezed by the thicker neck as it enters the neck of the chamber, causing the bullet to resist leaving the case as the rifle is fired. This is called excessive bullet pull. This condition can spike pressures to very high levels.
The inconvenient part of this procedure is, you have to load your ammunition to check the loaded neck diameter. If the loaded neck diameter is excessive you need to run an inside neck reamer into the neck, to remove excess thickness. To do this you have to pull the bullets on the over sized ammo. If you are lucky they won't have to be reamed. I actually prefer the first procedure with 7x57 brass. I usually don't get lucky.
I know there are not many 1901/02 Remington 7x57 rifles around but if my post would prevent one accident like this one from happening, it is worth my time.
Note: There does not seem to be any problems with the other 1901/02 rifles made in smokeless rifle calibers. That may be because the are all rimmed. Always check the headspace on older and military rifles before firing them.
Be careful out there ,
Doug

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