Converting 43 Egyptian Remington Rolling Block to a different caliber

[shafer44]

Ok, so I have 3 Remington rolling blocks, 2 #1 43 Egyptians and 1 #5 in 7mm mauser. The two #1's are black powder and the #5 is commercial powder. I am thinking of having one made into a 38-55, 43-70 or some other easier to load for caliber. Can all 3 be converted? I would assume that not much would have to change except barrel and chamber for converting the 43 Egyptians, but wouldn't it involve more with the 7mm being that the extractor would be for smaller head shells? Any way, I would appreciate your comments and I would be interested in knowing a ball park idea of what it would cost to do something like this. I am not a machinist, nor do i have machines to do this. I would also need to know who does this kind of work. Thanks.

[Don McDowell]

Rebarreling either one of those is going to take a new extractor, altho the 7mm extractor might work reaming it out to fit a larger rim diameter.
Any gunsmith worthy of the title should be able to handle the remodel on those rifles.

[John Taylor]

I usually have two or three in the works at a time. Most of them get a 45-70 barrel but my own is getting a 38-55. The last one I sent out was a 38 special. The older ones need to stay with a black powder cartridge pressure. The 45-70 is loaded to about 28,000 psi so many cartridges that pressure or lower will work in a #1. The modern 7X57 is loaded to 49,000 but that may be a little hot for the #5. The original loading for that cartridge may have been lower when the #5 came out and was changed about 1913. Best to stay below 45,000, like a 30-30 at 42,000. The other thing to think about is case diameter and bolt thrust, area of the case just in front of the rim X pressure equals bolt thrust. The longer strait walled cases sometimes give a problem with clearing the breach block and hammer, likewise the rim size. A 45-110 or a 50-70 may not clear on some rollers.

[shafer44]

Thanks John Taylor, that is information that I did not know. Well, most of it I did not know, I just bought a Pedersoli 1874 Sharps in 45-70 and it is 29000, but the SAAMI is what i keep my loads under and I usually don't come close to that. The #5, as I recall from shooting it a long time ago, key holed at 25 or 50 yards. The chamber or barrel is pitted or eroded, I think. Someone told me I could get it relined?? Do you do this work for others, or just for yourself?

[Drm50]

A few years back I did a Smokeless 7x57 RB to 45/70. With Numerich Buffalo Hunter kit. It went
together with very little problems. Gun shot very well. The only problem I had was that the smaller
smokeless action had not quite the clearance over the RB to insert a 45/70 straight in the chamber. It took a like wiggle to chamber a round. I had another one that was on 43 Span that
was already rebarreled to 45/70 that I had no problems with. I only used BP/ cast loads in all
the RBs.

[shafer44]

ok, thanks for the 7x57 conversion info. I had read something about it being possible, but could be a problem loading the shells into the chamber. How do i know if my chamber is eroded? I guess it would be the cerrocast stuff or whatever you call it?? Something i read said the throat was sometimes longer than the new production 7x57 ammo, so that can cause a problem?? How do you get around this? Would just fireforming the cases and then neck sizing with the bullet extended more out towards the lands help?

[ascast]

shafe44 7mm original rollers used a base dimension that was larger than modern 7mm, like 20 thousands IIRC. Mine would get 3 reloads, full sizing before head separation. So, don't full size.
7mm is a RIMLESS case, so the extractor has to move sideways to allow for you getting the extractor behind the rim after you have chucked it in the rifle. Something to consider in cartridge selection.
As for the neck issue, we all shoot cases that have been trimmed back, or just plain too short. You never hear anybody saying a case got stuck because of it. just sayin..
also plan on trigger jobs for any you plan to shoot

[shafer44]

thanks, again. I never shot the gun much because it tumbled the bullets. They were reloads, but with j-word and not boolits. I loaded them on the light end and did not have any pressure problems that i knew of, just keyholing or tumbling the bullets. I got a neck sizer after that and just neck sized them, but still had the problem. I may try again since now, using quickload, I have a better idea of what pressures to expect. The 2 egyptians that i have, have very hard triggers, however, the 7mm has a 4-5lb trigger. I don't know if anyone worked on it before or not, i have not had it apart to look and it is not too heavy, so I have not worried about it.

[Wayne Smith]

The first likely problem causing boolit tumbling is a boolit too small. You need to run a soft lead ball through that barrel and measure the results. Don't try to use a wooden dowel to do it, get a 3/8" brass rod long enough for your barrel, oil the barrel and knock the slug through. Now you know what diameter you need for a boolit.

[shafer44]

ok, I slugged my barrel and it came out 0.2864. I know the j-word bullets were .284, is that enough difference to cause key holes and tumbling bullets? I don't have a mold for 7mm or I would shoot some cast to see if they make clean holes. I may have to go onto the S&S and see if someone will sell me some boolits. If i get some cast, what should i try? .288?

[marlinman93]

7mm is .474" and .38-55 is around .502", so an easy rework of the extractor. The smokeless 7mm action is a little stronger also, and would make a great choice to rebarrel too! Additionally the later Rolling Block 7mm receiver is thicker, and can be safely reshaped to an octagon top, if you chose to make it look more like a Rem. Sporting Rifle action. It would be my choice over the others, but I wouldn't worry about reworking any .43 BP action, as long as the calibers were appropriate.

If you figure out the bore diameter by slugging the bore, you might find it will shoot the proper sized 7mm bullet quite well. Of course that depends on the condition also, and if the crown is good too! A lot of military guns got treated roughly, and a nicked crown can create poor accuracy too!
My old Rolling Block in 7x57 liked a 287" cast 150 gr. bullet. Shot them well, but bore was .286" and most jacketed were .284" and didn't work well for my gun.

[smkummer]

If the barrel on your Egyptians looks good, you may want to reconsider. Mine shoots a .451 sized lyman 457124 (385 grains) wonderfully. I size this in 2 steps first with a .454 sizer and then a .451. 13 grains unique. Using reformed 32 gauge magtec brass. Very accurate and I plink steel plates at 200 yards with the factory military sights. Once the brass is formed ( did this with dies I had in stock), I only decap, prime, slightly flare if needed and seat the bullet on a charged case. No worry about crimping as its a single shot and the fat bullet seats and chambers fine. just my .02