45-70 Trivia

TLH

New member
This falls under the "For What It's Worth" category.
I recently bought a Marlin 1895, 45-70, "Guide Rifle". I had a chance to load
some rounds up for it last week and yesterday ran some across a chronograph and shot some for group.

It has been 20 years since I had loaded for the 45-70 so I checked some current manuals and decided to try Accurate XMR 2495 and IMR 4198. I used 405 gr,hard cast lead flat nose (Meister Bullets from Dillon). I wasn't shooting for anything Earth shattering so started with both powders around the center of the loading range.

I loader the Accurate XMR 2495 at 49.5 grs and the IMR 4198 at 30 grs with a half-grain polyester filler wad. Both had the same overall length at around 2.4 inches.

Last Sunday I shot with some friends at a very casual gathering. I shot someof both loads just plinking. The IMR 4198 was moderate sounding had no noticeable muzzle
flash and seemed to have a fairly light recoil. The cases were also clean and bright on being extracted from the gun. The Accurate XMR 2495 had a sharp crack, a lot of muzzle flash (very noticeable as the gun is ported) and the cases were very grimy when extracted. They also seemed to have more felt recoil (I think the recoil HAD to be my impression from the blast of the discharge).

So the next day at the range and with the chronograph I get ready to see how much hotter the Accurate XMR 2495 rounds were than the IMR 4198. I don't surprise easily but these did surprise me.

The IMR 4198 rounds gave me an average velocity of 1320 FPS with a spread for 5 shots of 88 FPS between high and low. The Accurate XMR 2495 ran out at 1233 FPS with a 5 shot spread of 107 FPS between high and low.

IMR 4198 that was quieter, had no muzzle flash, gave me clean cases on extraction and also shot five holes touching at 50 yards (separate test) ran about 100 FPS faster that the noisy, bright muzzle flash, dirty case Accurate 2495. I still think the XMR 2495 recoiled harder but I don't think that's physically possible.

I was shooting on a covered range though and the IMR 4198 and Garrett +P loads just went off. The Accurate XMR 2495 rounds were actually knocking dust and junk off the metal roof over the firing line.

Oh yes the Garrett 45-70 +P rounds. A friend of mine turned me on to this ammo.
The ammo is custom made in Washington State. I understand that their issue with Alaskan Fish & Wildlife with the Marlin rifle. Either way, I got interested and not being real bright ran the guy down. When I purchased it a couple months ago it ran $ 45 per box of 20 with a $12 shipping charge. The round is advertised as a 415 gr, hard cast (called Hammerhead), lead flat nose. I got a couple boxes and finally worked up enough nerve to test them with my handloads.

These rounds were impressive. They made some noise, as one would expect but had no noticeable muzzle flash. They ran out of the Marlin Guide rifle at 1768 FPS, with a 5 shot spread between high and low of only 47 FPS (1791 FPS high, 1744 FPS low). At 50 yards they shot into 2.5 inches and that was because I pulled two shots out. Three were touching and I called the fliers.

These are some impressive rounds. Anyway I thought the difference between the IMR and Accurate powders was interesting.
 
I'm not familiar with XMR 2495. According to Accurate's website the only extruded powders they caryy are XMP 5744, XMR 2015, XMR 4064, XMR 4350 and XMR 3100. Is this an older discontinued powder?
I've been using the 5744 with a 405 LFN (D&J) at around 1250 fps for cowboy shooting and plinking in a heavy octagonal barrel Rolling Block. It does well when I do my part though I've never fired it over 100 yds. Already has a rainbow trajectory at 100.
 
IF you are looking for some other hot load try Buffalo Bore they have 350 grn @2100 fps and claim to have 405 @2000 fps. I have not shot either but am considering the 350 for a moose hunt in the near future.
 
TLH, The 4198 30 gr load gave the exact velocity (1320 fps) I have listed in an old Gun Digest. However, the AA 2495 should have yielded a velocity around 300 fps faster than you chrono'ed. But the additional recoil, as you suspected, indicated a higher velocity than the 4198 loads. One thing to check is how far away your chrono was when you shot over it. You might be seeing the effect of the muzzle blast turning on the chrono and the bullet turning it off which can give false low readings. Could this be the cause? How close were the detectors?
 
Mal H,
That's an interesting idea. I'm ussed to checking handgun loads and set the chrono at 10 feet. I usually measure the distance but on this particular day had guys on either side of me so I just eyeballed it. I don't know if 10 feet is to close for these loads.
I would have thought though that the Garrett loads would have given erratic readings. Both the IMR 4198 and Garrett loads performed pretty much as expected.
The Accurate manual I used their # 1, big red softcover. It shows a print date of 1994. The XMR 2495 replaced 2495BR (indicated on the container).It's sure 'nough extruded as I expected ball powder.
Don't get me wrong here either, I use Accurate # 2 at 9.7 grs(240 LSWC)for my two S&$ model 29's. Great load, pretty consistant and burns very clean at around 1100 FPS in the 4" and around 1190 in the 6".
How do I run down those hot 45-70 loads ??
 
10 ft. should be fine. I have seen the false readings when the sky screens were set at 5 or 6 ft. However, don't rule it out yet. Since you got a lot of muzzle flash from the AA and not from the 4198 or Garretts, there might still be too much unburned powder causing the false reading. It could even be the flash itself since the chrono is looking for changes in light. I'ld try the same load again but with the screens at 20 ft., just in case.
 
I'll probably try the XMR 2495 again. I have the powder and buy bullets 500 at a time. Besides they are SO impressive to the rookies standing around... of course the more experienced shooters must have been considering shooting me for all the noise.
 
On rifles I usually run my chrono at least 15 ft away from the muzzle. I would put a little further but the physical limitations of our range prevent that (there is a creek running in front of the firing line). For handguns I usually run around 10 ft.
 
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