Can I safely use high pressure .45-70 data in .45-90?

[Naphtali]

Hodgdon, and probably all publishers of reloading data, classifies .45-70 reloads by the platform that shoots it: Trapdoor Springfield is the weakest; Winchester and Marlin lever actions being intermediate; and Siamese bolt actions and Ruger #1s being strongest. Can I safely use loading data intended for Ruger #1s in a US Repeating Arms M1886 .45-70 that has been converted to .45-90? What I'm asking is whether the additional capacity of the .45-90 cartridge compensates for the higher pressure shown by the data.

[Buckshot]

Hodgdon, and probably all publishers of reloading data, classifies .45-70 reloads by the platform that shoots it: Trapdoor Springfield is the weakest; Winchester and Marlin lever actions being intermediate; and Siamese bolt actions and Ruger #1s being strongest. Can I safely use loading data intended for Ruger #1s in a US Repeating Arms M1886 .45-70 that has been converted to .45-90? What I'm asking is whether the additional capacity of the .45-90 cartridge compensates for the higher pressure shown by the data.

................The issue here is pressure and whether or not the excess space in the longer case will mitigate it is really something that would require a pressure gun to find out. With smokless powder the 45-90 really has no benefit over the 45-70. Using the same 45-70 load data in a 45-90 WOULD result in lower pressures, but how much lower? Also, what will the excess room do to the accuracy and velocity variations?

If you used a filler, you're back to higher pressures. I have a Sharps chambered in 45-90 and that happened only to clean up a long 45-70 chamber. With smokless powder it does nothing that a 45-70 won't do. I just used book 45-70 loads with a filler and worked my way up until primer appearance looked the same as familiar 45-70 loads. I just had to use more powder to accomplish it.

.................Buckshot

[charger 1]

Its common practice to put a 22 short in a 22 LR chamber, all the way up to sticking a 458 WM into a lott chamber. We comfortably get away with this because its apples to apples PSI wise. Your doing the same thing with a shorter shell in a longer chamber, and will it reduce the given pressure of that shorter load? definately, but without gauging it in a proper gun you dont know if it was a 10,000 psi reduction or a 1 psi reduction. If it was only the later, well you know the rest of the story:(:(
I WOULDNT!!!!!!!!!!!!!

PS. I just realized after posting, you may wanta take a look at my avatar

[The_Montanan]

Only use published data:

http://img375.imageshack.us/img375/739/4590smokelessa0ao.jpg

[Naphtali]

Montanan:

Where did you obtain these data, Hodgdon's? Have you data for hard cast LFN/WFN 430-500 grains? I'm in Seeley Lake. How about you?

[The_Montanan]

Montanan:

Where did you obtain these data, Hodgdon's? Have you data for hard cast LFN/WFN 430-500 grains? I'm in Seeley Lake. How about you?

The data is from an old IMR reloading book a buddy of mine in Chester copied for me. I live in Kalispell.... dang I love your area.

Seeley Lake, has some good :coffee: and good :drinks: places :mrgreen:

Back when I was shooting 45-90 in smokeless powder, I contacted Mike Venturino as he is a BIG fan of the 45-90 and older cartridges. I contacted him because of data that was not published but bullets that I had on hand etc. Accurate Arms 5744 is the powder of choice for MV when he is using it and not shooting BPCR. I also contacted the makers of Accurate Arms ie Ramshot Powder in Butte, Mt to ask them if I could cross over and use published loads for the 50-90 vs the 45-90 and they said YES that the presure would me no differant.

Accurate Arms has a load for the 440-gr bullet for the 50-90 loadings in the PDF format at http://www.accuratepowder.com/loaddata_caliber_rifle.htm

Look at the powder load for the 45-90 for the 405-gr and the 50-90 and the 440-gr loadings. You will find a ballance load in the middle that you can start with and use.

I am no longer loading for the 45-90 but just 45-70's now.

I hope this helps.

[Naphtali]

. . . I live in Kalispell.... dang I love your area.

Seely Lake, has some good :coffee: and good :drinks: places :mrgreen: . . .

I hope this helps.A big help.

Kalispell, I believe, is similar to Seeley Lake except it has become ungodly expensive to live there. I'm 75 yards from state forest and less than a mile from Lolo National Forest. Ranges for shots are short, unless shooting cross canyon, and the terrain appears to be like upstate New York, circa 1758 with a bad attitude.

I'm picking up a Browning M71 and USRA M1886 Friday. I'm torn between converting the rifles to .50-110 or .45-90. My heart wants the .50-caliber, but my brain and bank account shriek: What're you -- nuts?!!

[The_Montanan]

Yep, know the area well, as I used to have a friend of mine that I helped during branding around Clearwater Junction several years ago.... dang my son is 19 and that was when he was 6 yrs old.

Man how time flies, don't it?

I got a couple of .50 slugs that a friend sent me, one recovered from the off side of the bison he shot at 168 yrds, very inpressive. Now if you stay .45 cal the bullets are easier to come by, but if you cast the .50 will be easy to cast for as well.

Either one is impressive with the business results.

[Naphtali]

Okay, I have the M1886. It is a USRA/Winchester in .45-70. A friend of mine has the same rifle, but his has been converted [slightly] to .45-90.

For about $60.00 conversion fee the M1886 action is capable of furnishing more than .200-inch additional case capacity in overall length when using Starline .45-90 brass. I do not know to what this translate in terms of additional powder or water capacity. Were I to convert and handload 400-410-grain hard cast LFN gas check bullets, what would be a reasonable estimate of improvement in safe muzzle velocity compared with what I can obtain from this rifle as it is -- in .45-70?

[KCSO]

From a practical standpoint just about none. I converted my Giibb's rifle from 45-70 to 45-90 as the longer case fed better through the magazine. In 45-70 I could shooot a 535 Postell bullet at 1850 fps and that was all I could stand! In 45-90 I sure didn't go any higher. With smokless I could find NO advantage at all 70 vrs 90. With Black power there was about 150-200 fps difference. If you factor in the extra cost of brass, dies and general availability this is not a usefull conversion. Remember you can get 45-70 just about anywhere. Forget about shooting 45-70's in a 45-90 chamber too. Oh they will go bang but accuracy with cast bulllets is almost nil and even jacketed slugs don't do real well.

To sum it up unless I was using strictly B/P I wouldn't bother with the conversion.