As far as I know the 1895CB is only chambered for .45-70. It's the 26" octagonal barrel model. Have you heard of other chamberings?
To answer the original question there are several numbers to which different sources subscribe. A couple are rather scary in my opinion. Even some loading data provided by at least one bullet manufacturer is on the ragged edge of long term use. I think too many people are trying to make the grand old .45 Government into a .458 Win. Magnum. It isn't and can't be without implanting jagged Marlin components in one's forehead.
All that said I believe loads somewhat under 40,000 psi are safe for regular use in the Marlin 1895CB. Garrett Cartridges, Inc. loads to a maximum average chamber pressure of 35,000 psi and his Hammerheads will shoot clean through a Cape Buffalo. To my way of thinking, what more could you possibly ask for? Why increase pressures beyond such formidable capability?
I recently stumbled across an interesting article on Real Guns. WWW.realguns.com/archives/036.htm
This in anteresting and insightful article on the 1895G. the discussion inludes high performance loads.
Disscusions of peak pressure, bolt thrust and a very interesting discussion of muzzle pressure.
This fellows thoughts on yield strength, safety margins and reality are very interesting and well thought out.
Check it out, I would like to hear your thoughts on the peak pressure and muzzle pressure thoughts in the articles.
Joe's research shows that rather small increases in powder charge can lead to quite large increases in pressure. This is something we all should know as handloaders but it's great to see just how much pressure and bolt thrust increase with hotter loads. I believe many reloaders take for granted that there is a large safety margin in data supplied by the powder and bullet makers. In some cases this may be so, but in the .45-70 Marlin I don't believe that to be the case.
I for one am happy to see it presented for all to read in black and white. Some of the .45-70 load data I've seen presented on the 'net is downright spooky. The argument made at RealGuns.com in the above referenced commentary is sound and should be taken seriously. A few extra fps aren't worth the increased wear on your rifle nor the possibility of serious injury.
Consider 40,000 the max. Fire one of those with the steel buttplate on the 1895CB and you won't want to do it often. Max loads should be approached with caution and used sparingly, both in the interest of the gun and your shoulder.
A forum community dedicated to Sport shooters, owners and enthusiasts. Come join the discussion about optics, hand casting bullets, hunting, gunsmithing, styles, reviews, accessories, classifieds, and more!