Bullets & Brass
Understanding 45-70 +P Pressures
column By: Brian Pearce | April, 25
Dan F., via Facebook
A: Congratulations on acquiring your first 45-70 Government, but I’ll bet it’s not your last! Regarding loads and suitable pressures for your Marlin 1895 SBL, if you study the Speer Reloading Manual No. 14 closely, it is for lever action rifles. It is held to 28,000 CUP, which is SAAMI’s maximum average pressure. (I do not recommend that data for U.S. Springfield Trapdoor actions.) In addition to the Speer data being suitable for modern lever actions, it is also intended for original Winchester Model 1886 rifles and original Marlin Model 1895s that were also produced up to 139 and 130 years ago, respectively, and during the black powder era.This data should only be used in rifles that are in good condition with proper headspace, etc. Please note that this data should never be used with Marlin Model 1881 lever actions.
As to the strength of your rifle, all Marlin Model 1895s produced since 1972 feature a round bolt and forged high-tensile modern steels. They easily handle loads that run 43,500 psi, which is the same as the 450 Marlin and only slightly higher than the 444 Marlin. The same basic action has handled other cartridges with similar (or higher-pressure levels), such as the 375 Winchester at 52,000 CUP.
Loading your Marlin to 43,500 psi will significantly increase performance. Accurate 2015 and Hodgdon H-322 powders are excellent choices for heavy 45-70 loads with the 400-grain Speer flatnose softpoint bullet. I would suggest using 56.0 grains of A-2015 for around 1950 fps or 54.0 grains of H-322 for about the same velocity. Neither of those loads is above 40,000 CUP. Both loads are compressed powder charges, which is a good thing as they will support the bullet’s base when cartridges are subjected to recoil and inertia in the magazine tube and prevent them from deep seating. A large rifle standard primer is suggested, with the CCI 200 used with the above data.
Powder Variances Lot to Lot
Q: About 15 years ago, I purchased my first pound of Alliant Reloder 22 powder and developed a load for my 270 Winchester that contained the 130-grain Nosler Partition bullet pushed with 58.0 grains. It is super accurate, and velocities are 2,950 fps. I returned to the dealer and purchased 9 pounds that were from two different lot numbers. When the first pound ran low, I switched to one of the other lot numbers and the velocity and accuracy remained the same.
I have now used up most of my 9 pounds and recently purchased an 8-pound canister. Using all the same components and load, the cases are now sticking, and there are other signs that the load is too hot, including very flat primers with the primer indent being cratered. I double-checked my charge weights and the accuracy of my scale, and it is right on the money. I had to back off the powder charge 2.5 grains to get the cases to stop sticking. I have not been able to chronograph these loads, but I would guess that velocities are now well below 2,950 fps. My question is, has Alliant changed Reloder 22?
B. Smith, Billings MT
A: No, Alliant has not changed the burn rate of Reloder 22. However, it tends to have a little larger burn rate variance from one lot number to the next, which can result in exactly what you are experiencing. I suspect that when you chronograph your 2.5-grain reduced-powder charge load that it is probably very close to the velocities of your original load. Your situation is a perfect example of why a chronograph is such an important tool for handloaders.
As a side note, due to the variances in powder lot numbers, ammunition factories always start with new data with each new powder batch (as well as bullets, cases and primers, etc.), which is tested for pressures and velocities and screened for other factors before loading ammunition. Powder manufacturers that supply canister-grade products to handloaders generally keep lot number variances to a minimum, as handloaders don’t usually have access to the sophisticated equipment found in labs and are at the mercy of published data. Again, a chronograph is a hugely important tool for handloaders. Let me know how your new loads work out.
Is There a Substitute Powder for Alliant 2400?
Q: I am an old timer and have been using Alliant 2400 powder since the 1970s. It has always been fabulous in the 357 and 44 Magnums. I even use it in the 44 Special with excellent results. However, I have not been able to find any for sale for several years. I found some during the COVID powder crisis, but the price was absurd. I often check with a local dealer, but it is always out of stock. It just doesn’t seem to be available anywhere. My supply is running low, so I purchased two other popular magnum revolver powders, but they just don’t work as well. Even worse, I just recently loaded up some 44 Specials and several of them were squibs. That has never happened with 2400. My loads use the 250-grain Lyman Keith cast bullet No. 429421 pushed to around 1,050 to 1,100 fps. My 357 and 44 Magnum loads are full house.
In the 357 I use the 160-grain Lyman Thompson cast SWC 358156 pushed with 14.5 grains. In the 44 Magnum, I used the 250-grain Keith bullet with 21.0 grains, both Skeeter Skelton loads. Is there a potential substitute powder that will perform equally with 2400? Please help, and thanks for the many great articles on sixguns.
P. Carver, Idaho
A: We have all missed 2400 and many have asked similar questions to yours! However, there are some excellent options that will give great performance and are readily available. For your 357 and 44 Magnums, use Accurate No. 9, which shares a similar burn rate with 2400, but is a spherical powder rather than an extruded powder. You can use the same powder charge weights of 14.5 and 21.0 grains in the 357 and 44 Magnums respectively. However, to keep pressures within industry standards, you must use a standard primer. Using a magnum primer will increase pressure. The Western Powders lab (now owned by Hodgdon) tested these loads with both standard and magnum primers, and their results support my comments. However, they choose to publish data using magnum primers including Winchester Small Pistol Magnum in the 357 and CCI 350 in the 44 Magnum. The reasoning is understandable, as most handloaders assembling ammunition for the 357 or 44 Magnum will make the incorrect assumption that since they are shooting a magnum sixgun, then they need magnum primers. You can actually increase your loads up to 14.9 and 21.5 grains respectively. Your velocities will duplicate or exceed slightly 2400 powder velocities and accuracy should be very good.
Regarding your 44 Special loads, like other slow-burning spherical powders designed for magnum revolvers, No. 9 does not burn ideally at lower pressures (which would be expected from the powder and load that you were using that was a squib load and is not published here). You must find a different powder for your desired 1,050 to 1,100 fps velocities. With the following suggested loads, you should be pleased with the low extreme spreads and accuracy. Using 250-grain Keith bullets, try 8.5 grains of Alliant Power Pistol for 1,050 to 1,075 fps in most sixguns. Other loads that will give similar velocities include 9.2 grains of Vihtavuori 3N37, 10.0 grains of Accurate No. 5, 11.5 grains of Accurate No. 7, and 9.0 grains of Hodgdon Longshot (which actually goes just over 1,100 fps). Naturally, use standard large pistol primers with CCI 300 used herein. I hope that the data helps. Thanks for taking the time to read our magazine.