I just purchased a Siamese Mauser in .45-70 that has been sporterized (turned down bolt, sporter stock, new 1-18" barrel, scope mounts, 4 shots in the mag + 1 in the tube) and have some questions. I'm mainly going to shoot GC cast bullets from it at steel gongs as well as a backup gun.

1) Has anyone here had one and what were your impressions?
2) What bullet weight is "optimal" for a 1-18" twist barrel?
3) What is the pressure limit on the siamese mauser actions in 45-70?
4) Any 'pet' loads?
5) Anything I should look out for?

I've been looking for one for a while and just picked one up at the local gunshop that caught my eye.

Thanks,
BMG

Check that it feeds and ejects reliably particularily with fired cases. Most will jam on ejection. The fix is to mill out the rear action port. Mine is a tack driver with the old 50 grs of IMR3031 and 500 Gr RCBS RN Cast bullet or 500 gr Hornady jacketed bullet. Like all Mausers of that vintage I'd stay below 50Kpsi. Your best bet is a 400 gr bullet at 2100fps. That is about it in reality. Don't try for 458 Win Mag pressures in a Siamese Mauser as the lugs will set back way before you get there. Or after 5 or 6 shots!-Rob

I've got one that I had built a lot of years ago. It's never fed well unless I had my fingers in the loading port making sure the cartridge was straight. The rifle proved accurate using the 405 grain cast RCBS and the Lyman eqivilent. The Lyman 500 grain bullet was good but the recoil was more then I enjoyed. The bullet I found to be the most accurate was the 445 grain gas checked from Lyman #457102. This bullet was great with 50 something grains of IMR4064.
Jim

Robgunbuilder
Who would be a good gunsmith to work on this rifle and correct the feeding problem.
Jim

Dennis Olsen ( how old are you and do you hve enough years left)? Maybe AHR or John Ricks. I can supply details on what needs to be done to both of them, but I don't do commercial gunsmithing myself.-Rob

BMG
I have had very good luck on game with the 350gr. Hornady RN at speeds from 1890fps [45/70] to 2330fps [450 No2]. This RN has fed perefectly in lever actions and bolt 458 Win Mags.

I took a deer with mine this year. Load was 50 grs of RE7 behind the Hornady 350gr RN. To use an overworked word, the results were awesome. I have in the past loaded it up to 59grs of 3031 with the same bullet, but see no point to pushing it. After all, the .45-70 is not going to have a "flat" trajectory, and it isn't a .458WM. With the above RE7 load, the rifle is quite accurate, and pleasant to shoot. With the modest Weaver 4X scope, 10 rounds or so will eat out a 2.5" hole in paper at 100yds. I have not tried cast bullets, but that is on the agenda. Mine does have feeding issues. One must be careful loading the magazine, and run the bolt with authority. Otherwise it will jam. I sure wish I knew someone to send it to for a fix for that, as I sure do like the rifle...