45-70: Loaded for Bear

[g.man10mm]

A few months back, my brother in Alaska asked me if I could come up with a good alternative to the excellent but pricey Buffalo Bore 350 and 430 grain loads he'd been using in his Marlin Guide Gun for years to hunt both black bear and grizzly in Alaska. I figured it was worth a shot, and since a couple of folks in another thread asked me to share what I learned, I figured I'd do it here.

Goal:
To create a 45-70 "Magnum" load that is safe and reliable in the Guide Gun, will shoot 3 MOA or better, and be effective on Grizzly out to 100 yards.

Result:
A 45-70 round shooting a 24 BHN gas-checked 385 gr WFN at 1842 FPS capable of putting 3 rounds into .976 at 50 yards from a standing, braced position. Cost per box of 20 was around $7.

Disclaimer:
There are many wiser folks on the forum who are far more meticulous than I am. I have a philosophy of “Perfection is the enemy of good enough.” I hate to see my projects languish through a combination of my limited free time andanalysis paralysis. I wanted to put together a round based on safe procedures, reasonable assumptions, do some “lab” testing, then take it to the field for the real deal next May. (Backed up by my “known good” 340 Weatherby, of course.) If you decide to use this info as a reference, please ensure that you work up safely, test for yourself, and use sound judgment along the way. Also note that I was using small primer brass, which should provide an additional safety margin, assuming you would get the same results in conventional 45-70 brass could easily be dangerous.

Supplies and Equipment:
Marlin Guide Gun (18”) with Leupold 2.5x Scout Scope
Master Chrony
LBT Hardness Tester
QuickLoad Internal Ballistics Software
NOE 460 405 WFN GC RG2 Mould (solids) - info and pictures in link http://noebulletmolds.com/NV/product_info.php?cPath=42&products_id=665
Buffalo Bore 1x Small Primer Brass
IMR 4198
Winchester Primers
LBT Blue Soft Lube
Lyman T-Mag Press
RCBS Dies
RCBS Chargemaster (all charges individually weighed to the 1/10^th grain.)

Next: Methodology and Assumptions

[g.man10mm]

Methodology and Assumptions:
I started with the (very safe) assumption that Buffalo Bore and Garrett Cartridges know more about this topic than I ever will, so I looked at what makes their rounds successful for guidance. I modeled my alloy selection after theirs; I tested the BB rounds I had on hand at 21-22 BHN. Garrett indicates on their site that they use a low antimony alloy at 25 BHN. I messed with alloys until I settled on a 10:1 mix of range scrap and linotype, water dropped and aged for a few weeks until they reached 23-25 BHN. This resulted in a hard, straight-and-deep penetrating 385 gr bullet that shouldn’t shatter when hitting heavy bone.

http://www.garrettcartridges.com/4570.html
https://www.buffalobore.com/index.php?l=product_list&c=35

I further assumed that the 385 gr NOE WFN would be a good compromise between the 350 JFN and the 430 WFN.

Newspapers were the best I could do for a penetration testing medium, so they would have to do.

Perusing Lyman # 47 and Lyman CB Handbook, It looked like IMR 4198 was going to be the best choice from the powders I had on hand, so I decided to start there, and only worry about trying to find an alternative if I wasn’t happy with the results.

I ran all the numbers through QuickLoad, and cross-referenced with loading manuals (interpolating from 350 and 405 gr cast load data.) and carefully inspected cases after each shot. QuickLoad very accurately predicted velocities in this case. So I assumed that the pressure figures were similarly valid, but chose to err on the side of caution anyways.

I started at 36 gr of IMR 4198 and worked up in .5 gr increments as I approached max, firing only one 3-round group per charge weight, out of deference to my limited supply of powder (since corrected, luckily) and my shoulder.

Next: Load work-up, velocity and accuracy figures

[Tatume]

Why did you choose the relatively fast IMR4198? Did you consider IMR3031?

[pmer]

I went with a 405 grain at 1500FPS air cooled 50/50 for blackies here in Minnesota but I'm not seeing any bear in the game camera. Had 7 big racoons pounding down frosting and licourish (spelling?) like its going out of stlye. I'll use the load for white tail next month.

[g.man10mm]

Why did you choose the relatively fast IMR4198? Did you consider IMR3031?

Good point, I probably should have mentioned it up front. Short answer: availability.

Based on my initial perusal of the loading manuals, 3031 looked very promising from a velocity/pressure standpoint, I just couldn't find any locally. Luckily, I found 2 pounds at the local ranch store last week. I wanted to have something good enough in the bag before I worried too much about wringing the maximum performance out of it. The reality is that work/life could easily intervene and bring all my efforts to halt, and didn't want to get caught without a solution when time to hunt rolls around. While I feel like the current load meets the "good enough" standard, working up and testing a load w/ 3031, and a few other details, are on my list of things to follow up on.

[Beagle333]

Excellent to know. Thanks for the writeup on it! I would like to load a box or two of heavy 45-70's for my Guide Gun, just to have them. Until I get my shoulder fixed, I won't be shooting any bear loads, but I would like to have some info handy. I got 4198 and 3031 in stock.

[Ricochet]

Good thing about the .45-70 is that you really don't need to wring the maximum performance out of it for it to be effective. I used to pound my shoulder purple with maximum loads in my Marlin (a 1973 model with a hard butt plate with a pointy heel), but I've mellowed with age. Plus, I have a brass framed Century .45-70 revolver that isn't intended for the heaviest loads, and I don't like keeping around ammo that's OK for the Marlin but abusive to the Century. Presently my favorite is the Lee C457-500-RF unsized with no gas check pushed to 1400 FPS with a load of surplus WC680. I also use the 330 grain Lyman-Ideal Gould HP (about 340 in my softer alloys) and a Lee 457-325-RF that I bought off their closeout page, it's their 340 grain design with the base shortened a bit. The only thing wrong with both the Lee moulds and the Lyman ones (meaning all that I have for the .45-70) is that they cast right at .457" and the factory specified groove diameter for the 1973 8 groove version of the 1895 .45-70 Micro-Groove barrel is .4584". Mine is right on. So it tends to lead a little more than I like. I actually haven't tried checking the Lee 500 grainers, the mould is fairly new to me, but using a polyester fiberfill case filler helps a lot. I'll always have a soft spot for those Gould HPs, they're the first bullets I cast. They're pretty explosive at the .45-90 velocities I shoot them, though, and I wouldn't use them on a big bear. Wouldn't feel under gunned with the 500s at 1400.

[Ricochet]

BTW, I wrapped my right arm around my back getting off a Harley in an unapproved fashion. Upper humerus was replaced with metal, and the big spiral spearlike pieces of the shaft were wired together. Amazing that the arm works so well after a year of Physical Therapy, for which I'm grateful. I used to beat my shoulder purple with the Marlin while recovering from that. It hurt, anyway. My Physical Therapist would look at it and just shake his head.

[g.man10mm]

Load work-up, velocity and accuracy:

Bullet Mould: NOE 460 405 WFN GC RG2
Alloy: 10:1 Range Scrap:Linotype, Water-Dropped, 24 BHN
Bullet: 385 gr .459 WFN GC, LBT Blue Soft, HDY Gas Check
Brass: 1X Buffalo Bore Small Primer
Powder: IMR 4198
Primer: Win SR
OAL: 2.488
Crimp: Heavy Crimp (Visually duplicates the BB Crimp) at the crimp groove

Elevation: 4800 MSL
Temp: 21 Aug = 79 degrees F; 28 Aug = 82 degrees F
Wind: None to minimal

Test Weapon: Marlin Guide Gun (18”) with Leupold FX-2.5 Scout Scope
Shooting Position: Standing, braced (support arm braced against truck cab)
Range: 50 yards
Loads 1-5 were fired on 21 Aug 14, and groups were not measured, but none exceeded about 1.5”
Loads 6-9 were fired on 28 Aug 14.

Charge IMR 4198; velocity; average; group size
1. 36.0; 1595,1550,1630; 1592
2. 37.5; 1658,1675,1681; 1671
3. 38.5; 1680, 1671; ND 1675
4. 39.5; 1710, 1710, 1724; 1715
5. 40.0; ND, 1736, ND; 1736
6. 40.5; 1763, 1764, ND; 1763; .488
7. 41.0; 1785,1783,1796; 1788; 1.178
8. 41.5; ND, 1806,1797; 1801; 1.038
9. 42.0; 1835,1835,1857; 1842; .976

Recoil went from stout to bone-crunching. I don’t know that I can put much value in the accuracy numbers as far as one load being better than another, based on shooting position and the cumulative effects of recoil. I had no interest in shooting this thing from prone or benched merely for science. Bottom line, I think, is that any were good enough from a representative field shooting position. Groups were measured with calipers, and bullet diameter subtracted.

Every case was inspected after firing, no signs of high pressures were evident, and cases extracted under normal operation. I likely could have continued carefully going up, but I’m satisfied with the current velocity and accuracy.



Next: Penetration testing, conclusions, and follow-up actions

[osteodoc08]

Most excellent write up. I use the same mold with a full load of Varget.

[jmort]

Here is some data from the Linebaugh Seninars. If you add in the Bone Box the results will be more real world. These results were with wet newspaper.

http://www.handloads.com/misc/lineba...tion.tests.asp

I don't know if it will cycle, but a big heavy bullet, 500 grains plus, at reasonable speed works real good. I am no recoil junkie, so 500 grain WLN at 1,350 would be perfect for me. That should go end to end and blow through on a broadside. You will see bullet "failure" at higher velocity in the Linebaugh tests with most hard-cast bullets for the .45-70. The Punch bullets are expensive, but give incredible results as the Punch bullets will not fail.

[Jupiter7]

Thanks for the write-up so far. Just got the NOE 46-405.

[g.man10mm]

Good thing about the .45-70 is that you really don't need to wring the maximum performance out of it for it to be effective.

I'm definitely with you on that! I was actually pretty happy with the initial load of 36 grains and loaded up 40 rounds for myself that I'll probably try to use for black bear in AZ one of these years when I'm actually in town when the season kicks off. I defer to experienced Alaska hunters on Grizzly issues, and since my brother had a lot of confidence in the BB loads based on shooting bears with them, I wanted to get this load up in that neighborhood. But like you said, the body pays a price for that; physics is a harsh mistress.

[Jevyod]

Excellent write-up! Much good info here and will give me a jump start into loading my Accurate 46-415V bullets!

[Tatume]

Take a look at Hodgdon data for lever action rifles. They get very close to 2000 fps with many powders, including IMR4198, and a 400 grain jacketed bullet (and even break over 2000 with H4198!). You can interpolate these data to cast bullets.

[Doc Highwall]

I have used the old Elmer Keith loads with IMR-3031, starting at 48 grains and worked up to 53 grains.

If I recall correctly with a 1-3/4x5x Redfield scope I was able to shoot 2" to 2-1/2" groups and the recoil was definitely there.

I have used Varget with 405 grain Remington bullets that have shot great sub 1" at 100 yards with my Marlin that has a 16.5" barrel.

[g.man10mm]

Penetration testing, conclusions, and follow-up actions:

Unfortunately ,my penetration testing left a bit to be desired, which is ironic since penetration and bullet durability are such important aspects of the whole thing– lesson learned. I used a 24” long cardboard box with tightly packed newspapers and magazines (pages perpendicular to bullet travel), doused with 4 gallons of water, with 2 1 gallon water jugs lined up in front. I consider the results encouraging, but not really conclusive or useful for comparison/evaluation purposes.

I had set aside an extra round at 39.5 and 42 specifically for this purpose and fired the 42 gr load through the jugs and into the box at about 10 yards. As you may suspect, I didn’t recover the slug. The good news was that the bullet penetrated straight through, and I didn’t find any fragments in the box/pages. The exit hole was roughly 2x the size of the entry, but I couldn’t say is that was indicative of expansion or just crushing force/ripping/tearing. I’d like to try again with a much larger stockpile of paper, and maybe add in some scrap plywood and see if I can’t recover a few slugs and ensure that they are remaining intact under a little more stress. If I had to get on a plane to Alaska tomorrow, I’d feel comfortable that this round would perform, but I’d still like to work with it a bit more before I start loading in quantity.

RANGE VELOCITY ENERGY(FPE) TRAJECT COMEUP MOA
Muzzle 1842 2900 -1.5 0
50 1735 2572 0.7 -1.4
100 1632 2278 0 0
150 1536 2016 -3.9 2.5
200 1444 1783 - 11.6 5.5

The other things I’d like to examine/refine:

Work up aload with IMR 3031 and maybe look into the AA line of powders when they start showing up in stores again.
Chrono and confirm zero at 35-45 degrees F.
Shoot at various extended ranges to confirm the accuracy of the ballistic charts, and just see what a realistic range might be for deer and other less demanding critters that might be a bonus opportunity on a bear hunt.
Not to state the obvious, but, finally test it on a bear!

Conclusions:

45-70 is an absolute delight to load for, but extended shooting/testing of heavy loads is less fun.
The NOE bullet and IMR 4198 are capable of good accuracy, more than I will really need for this round’s intended purpose.
Leading was a non-issue across all velocities tested.
With good cast bullets, you can create a reasonable facsimile of premium specialty rounds for about 10-20% the price.
I definitely believe the round could be improved and refined, and probably pushed another 100 FPS or more, but I’m inclined to believe it will do the job as is.

That’s all I have for now, but I’ll be sure to post any new results I get. Thanks to all for reading, asking questions, and the many kind comments. I’ll likely do this all again when my 1^st .358 Win (BLR take-down) and mold get here next week.

[Bjornb]

Great writeup! My Marlin 1895 (custom slicked-up by Goodsteel) is my rifle of choice for both moose and bear (Alaska hunts) every year. I'll be testing your loads!

[smoked turkey]

Great write-up & information here. It could be a "sticky" for future reference. Many thanks to you and your shoulder for the load development work.

[grouch]

My only suggestion is that you might want to try a softer alloy. The old Winchester 45 90 ammunition box recommended 16:1 lead and tin, my 45 70 shoots extremely well with 18:1, and I'd guess, based on using that alloy in 30 30's with faster twist barrels, that it should easily achieve any velocity you'd want to shoot in a 45 70.
Grouch