IMR 4320 in the 45-70

[Red River Rick]

Looking for some loading data using IMR 4320 in the 45-70 with a 300 -325 gr cast bullet. Thanks.

RRR

[longbow]

Sorry, I thought I might have something to help out here but none of my current books show 4320.

I did have an old Hornady manual about 30 years ago that listed 4320 for .45-70.

I had started out with a Siamese Mauser conversion in .45-70 using a load of IMR 4227 from the same book for 500 gr. bullets. It was an economical load giving good velocity and being a thirfty lad I decided "less powder, less cost, same velocity". What entered into the equation after I pulled the trigger was severe recoil!!!!!!!!!!

The IMR 4227 may have been a safe and economical load but it really hurt! So, I looked in the same book for the slowest practical powder and IMR 4320 was it. More powder, more cost but recoil became a big push not a sharp jab. I was loading for 405 gr. and 500 gr. bullets.

My current Hornady manual does not show either 4227 or 4320 for .45-70 nor do any of my other manuals.

Anyway, maybe someone here has a '70's vintage Hornady reloading manual and if so you will likely find 4320 loads in it.

Have you tried the Hodgdon site?

Longbow

[wiljen]

Try 46-53.5gr with up to a 405gr bullet.

53.5 is book max for the 405

[Red River Rick]

Longbow/Wiljen:

Trying to find loading data using 4320 ain’t that easy. The only reason I’m looking is because someone gave me 5 lbs and I thought perhaps I could burn it up in my 86’. I don’t have much else to use it in, all the my other calibers have seasoned loads so I stick with them.

I found three (3) different loads in my quest out of up-teen books. I found the load Wiljen posted, it was on the Dupont IMR site. And the two other loads are in Lyman’s 45th edition Reloading Handbook.

IMR 4320 45.0 – 51.0 max 405 gr “J” bullet 1342 -1720 fps
IMR 4320 47.0 – 54.0 max 300 gr Short Jacket 1524 -1782 fps

The 300 gr “Short Jacket” makes me believe they mean a half-jacketed bullet. So I’m wondering if it would safe to use this data for a 300 gr GC bullet, maybe reduce the load by say 10 -15%.

I checked Hodgdon’s 2008 Annual Manual and no luck, same with their website, no data for IMR 4320.

It’s not a big deal, I just thought if I could use this powder in the 45-70 round, that would be great. I have all kinds of other powders on hand so I’m not stuck.

Thanks for the help guys, much appreciated.

RRR

[longbow]

Red River Rick:

It just occurred to me that you didn't say what .45-70. My Hornady manual classes .45-70's as follows:

- BP equivalent for Trapdoor Springfield and other old BP guns
- Marlin 1895 and equivalent strength guns
- Ruger #1, Siamese Mauser, etc

No loads using IMR 4320 though.

I dug some more and turned up my old Speer #10 which has loads listed for IMR 4320 for the Marlin 1894 class and Ruger #1 class for 405 gr. jacketed bullet only:

- Marlin = 51.0 to 55.0 gr. @ 1630 to 1755 FPS
- Ruger = 57.0 to 61 gr. @ 1810 to 1931 FPS
- Speer does not list BP class guns or lighter than 405 gr. bullets

Obviously you don't want to be using Marlin or Ruger class loads for a BP class gun.

I used to run jacketed loads behind plain base cast bullets with no problems.

Longbow

[Red River Rick]

Longbow:

I want to use these rounds in my Win 86', so I'd like to keep these loads down to safe operating pressures, hate to blow her up. It just may be that this powder may not be suitable for the lighter bullets (pressures).

I'm thinking that I'll try about 45.0 grs, load a few rounds and head to the range on Saturday.

Thanks again.

RRR

[Scrounger]

IMR 4320 is just a tick slower than 4895. Starting data for 4895 should be a safe place to start, or drop it another grain or two...

[Red River Rick]

Thanks Scrounger, a good option, that never crossed my mind.

I recieved a whole wack of RCBS 325 gr FNGC bullets, cast in WW, from Dan at the Bullshop and I must admit, these a profesionally cast and mighty fine looking bullets, A+.

I'm leaving next Friday for my annual carbou hunt and was wanting to use these bullets on them varmits. Since these Bou's aren't very big critters a heavy bullet isn't needed.

RRR

[JesterGrin_1]

http://stevespages.com/458_1_350.html This might help. :)

[muffinman]

My Hodgdon #26 list 56 grains Imr 4320 as a starting load and 58 as max for a 350 grain bullet. I have used it with theLyman 457643 weighing around 410 grains of my alloy. My best groups were at 46 grains , well below Hodgdons starting load of 52 grains for the 405 grain bullet. Looks like I started at 42 and worked up to 48.

[Le Loup Solitaire]

Hi, Vintage Lyman cast bullet handbook has listing for mold # 457122 wich is a 325 grainer with gas check. Forty-five (45) grains shows velocity of 1485 fps and 52 grains (Max) gives 1675 fps. Good shooting. LLS