A New .45 Project for Deer Season

[Aszerigan]

A New 45 Project

I’ve been mulling over some wildcat cartridges designed around the change in Indiana’s deer-legal cartridge specifications. I’m a big fan of the 458 Socom and 450 Bushmaster for terminal ballistics and accuracy, but the idea of hunting with an AR platform isn’t high on my list. Nothing wrong with it, I’m just a traditionalist when it comes to the feel of a wood stock.

Several customers have quietly offered preferences over the past several weeks. Friends offered some suggestions for what might work with their platforms. All seem to have an affinity toward their big bore lever guns - a direction I was heading - but since the 45-70 is not a legal DNR cartridge for deer in Indiana, a similar cartridge that could be worked to fire in their existing rifles may be a solution. Enter the new .458 round.

Description:

The round is a trimmed 45-70 casing, cut down to 1.785”, and neck sized to 0.4877" (outside dimentions after seating), at a length of 0.470" from the case mouth with a new sizing die. This allows for positive neck tension while holding the test bullets securely. The straight neck sizing is needed since the 45-70 is a tapered cartridge. At 1.785", the 45-70 has an external diameter of 0.4785", so the slightly straightened neck has a differential from the original casing of 0.002". This should seal upon firing.

Unlike the 458 Socom and 450 Bushmaster, this round is a rimmed case designed for lever and break action rifles.

The internal case volume of the comparison cartridges is as follows:

38 Special - 24.3ml
45 Colt - 46.5ml
New 45 - 65.0ml
45-70 Gov't - 80.0ml

Comparison with the 45-70 Gov't

The 45-70 is a much more pleasant round to shoot than most people think. Unlike the standard 458 Socom which is usually loaded with magnum pistol / shotgun powder (to accommodate a RR 16" Midlength barrel) which gives it a sharp and somewhat unpleasant recoil, the 45-70 is designed for longer barrels and uses rifle powder. This gives a more elongated rifle "shove" than a shotgun style slap. The new 45 cal cartridge will use the rifle powder as well, and be tuned and chrono'ed in 18.5" and 22" barrels.

OAL 45-70: 2.532" (JHP)
OAL New 45: 2.305" (FTX)

The first testing gun will be an H&R Handi-rifle 45-70 in 22". This was chosen specifically for its very stout breech and thick barrel. Should the pressure levels go catastrophically wrong during testing, I believe this barrel can handle it. If it can't, then we've lost a $300 testing rifle, not a $750 lever gun. This first rifle will be used for load development, starting at 40.0gns of H4895, and moving up toward 50.0gns of H4895, observing chronograph speeds and checking for pressure signs at 0.3gn increments.

Assuming the cartridge can produce velocities between 1700-1850fps, as well as contain the pressures needed to produce said velocities, I've purchased a Marlin 1895G in 45-70 to do further testing. Already, the rifle has been tested to work with feeding and ejecting the shorter rounds. The true success will be testing the accuracy through this rifle. If 1.5" groups at 100 yards can be produced with this new cartridge, it will be considered a success.

Points of note:

The main concern that arises in developing this round would be the "jump," or the amount of forward bullet travel before engaging the barrel rifling. Although you can shoot 44 Special in a 44 Magnum rifle, 38 Special in a 357 Magnum rifle, etc, force hitting the rifling (mass multiplied by acceleration) in this cartridge may prove too be difficult to overcome with very heavy bullets. This can affect accuracy as well as velocity and point of impact. This will need to be tested during the preliminary stages of load development. A shortened 45-70 chamber barrel can be drilled, and this may be pursued if the outcome is not positive. Testing will tell.

Aside from this concern, I can't foresee any potential problems with this round. The sizing is correct, the chamber sealing should occur, and the case certainly has enough containment space to produce the desired velocity for a bullet of this weight.

I'm going to trim, load and test (hopefully) 50 rounds this week. That should provide a starting point for load development. This may work, or it may be an absolute failure. I'll be posting the result here with some videos of the testing as time allows.

Conclusion:

This cartridge is the (slightly) little brother for the 45-70 Gov't. It follows all the new guidelines set out by the IN DNR for a legal deer hunting cartridge. It feeds properly in lever action 45-70s. It's internal volume is 150% of the 45LC. It fires the same bullet as the 458 Socom, and a significantly heavier bullet than the 450 Bushmaster. It shares properties with the 458x2 American, a now defunct Vietnam-era cartridge, although it should produce significantly higher velocities.

If testing is a success, the cartridge will be named and submitted to the DNR for approval.

I'll post more testing stats when I have some time to shoot this weekend. Thanks for reading and check later in this thread for the results.
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Testing, Day 1

I began the testing on the new .458 cal round today, nicknamed the '.458 Chester' for testing purposes (until it gets a new name.)

Started at the shop this morning by loading 45 rounds in ten different charge weights. Primed, trimmed and sized 45 cases of .45-70 Starline Brass. Necked each (according to the original post) down to 0.4877" external diameter.

Trimming the 45-70 Brass down to the .458 Chester.

I meant to say "0.50 in diameter," not circumference. Sorry or the mistake.

http://www.youtube.com/watch?v=Z7e5sFmJFQg


Trimming in Real Time :

http://www.youtube.com/watch?v=0RwHHTirQ2E


Necking the .458 Chester Round:

http://www.youtube.com/watch?v=xmxJlMN40rg


Picking Charge Weights : Special thanks to Broom_JM for his input and expertise. He was totally right about the velocity vs powder capacity.

http://www.youtube.com/watch?v=UbOEM83T0ks


Inspection of the loaded rounds:

http://www.youtube.com/watch?v=i7tbL5zzGFw


Testing H4198, 34.0-35.0gns:

http://www.youtube.com/watch?v=-PQQLoJlCYM


Testing H4198, 35.3-36.2gns:

http://www.youtube.com/watch?v=Zi1rrv8yp7g


Testing H4198, 36.5gns - 37.5gns

http://http://www.youtube.com/watch?v=-3F67gUyqoI

 

[stlaser]

Sweet! Way to step to the plate on this one Andrew.

 

[Broom_jm]

That was an excellent write-up...very thorough and well thought out!

Like all great ideas, there is parallel development going on with the 45/70-1.800". I've been helping out a guy on another forum who is doing a lot of the same kind of testing, although he's using longer cast bullets to keep them closer to the lands, largely eliminating the one main concern with this particular wildcat idea.

Something that really surprised me when I started looking into the notion of a 1.8 inch Indiana-legal round, in 44 or 45 caliber, is that the pointed, Flex-Tip (FTX) bullets have virtually no advantage over hollow-point (XTP) or WFN (wide-flat nose) cast bullets, in terms of trajectory. The FTX bullets sure look cool, but their ballistic coefficient just isn't better enough to make a real difference at ranges for which this kind of round is suitable.

I do like the idea of sticking with a standard chamber, like a 35 Remington, 356/358, or 45/70 and just trimming brass that will meet the 1.800" limit. This allows you to avoid the cost of a custom chamber, lowers the cost of the dies to having them shortened on a mill or lathe, and when it's all said and done, you've still got a factory-chambered rifle that is easier to sell, should you decide to do so.

This particular 'cat would basically give you modern inline muzzle-loader performance from a gun you don't have to fuss with cleaning, like you do a ML. That is a pretty cool deal, if ya think about it and should make this idea quite appealing to at least a few Hoosier deer hunters.

 

[dom1104]

Name it.....

The .45 Profire Short Magnum.


But what I really wish you would call it is

"The .45 Length Isnt Everything".

 

[Slow Hand]

I had the same thought when the 1.80" rule came out but didn't have a .45-70 around to play with. You are using a case slightly longer than a .475 Linebaugh Maximum so you should see similar ballistics. I'm betting with modern powders, you'll be nipping on the heels of the full length .45-70.

Looking forward to hearing some results!

 

[rockhopper46038]

Had occasion to view a little of the development work on this at the shop yesterday and this is really impressive!

 

[Indy_Guy_77]

Fantastic! And I'm not even a hunter...or reloader!

Question though:

When coming up with your load recipe, did you just decrease the powder levels by ~20% or so in direct proportion to case volume between the "parent" and the newby? Or go ~20% less and then subtract a further safety factor? Just curious.

-J-

 

[SWAMPMASTER]

tagged

 

[Aszerigan]

When coming up with your load recipe, did you just decrease the powder levels by ~20% or so in direct proportion to case volume between the "parent" and the newby? Or go ~20% less and then subtract a further safety factor? Just curious.

I figured with a 20% decrease in overall volume, a 25% decrease in starting load data for the 45-70 would be appropriate. Hodgdon lists the 45-70 load as H4895 and 53.0-59.0gns (c) with a 350gn bullet. Starting slow with a chrono and working up is going to be fun.

 

[Broom_jm]

I figured with a 20% decrease in overall volume, a 25% decrease in starting load data for the 45-70 would be appropriate. Hodgdon lists the 45-70 load as H4895 and 53.0-59.0gns (c) with a 350gn bullet. Starting slow with a chrono and working up is going to be fun.

Hmm, that's interesting. With H4895, that should work "ok", but I really think you're leaving something on the table, using such a slow powder, with reduced capacity. QuickLoad suggests you'd get better performance with a faster powder, given that you have less grains burning to create the same MAP, in a smaller space.

I'm guessing your case capacity at around 62 grains, since the 45/60 is 1.890" long and holds 65.5 grains. If that is accurate, and it really can't be far off, powders in the range of H332, RL10X, RL12 and even as slow as 4198 should work well. Some of that depends on your seating depth and what pressure range you're working toward, but with H4895 you're really running out of capacity before hitting ideal pressures.

If I was working with a shortened 45/70, I believe I'd go with a case full of RL12, for mild recoil loads, and RL10X for a little more velocity. If I wanted some hot loads, meaning in the ~35,000psi range, for a strong single-shot or certain lever-action guns, I'd step it up to RL7 or 4198.

Shoot me a PM if you'd like to rap on it.

Jason

 

[Hookeye]

If it is under 1.8" why submit it to the IDNR?

FWIW, on the lesser power scale there are guys running AR's in .45 Winmag (for those who want .44 mag type of power, in AR platform).

 

[Titanium Man]

Good read............very informative. Thanks!!

 

[william]

I had a buddy messing around with this last winter after he first heard of the new COAL changes. He had a load worked up and I shot a few with him out of a Marlin 1895. They cycled fine but we didn't get wery good accuracy out of it. Don't know if he kept trying or just gave up. I'll have to call him up and see if he ever got it dialed in.

 

[Denny L]

I was looking at the 450 Marlin for a similar project. Trim the case to 1.8 and work up a load

 

[djones]

I'm excited to see your results. I've been kicking around a 45/70 but wanted to get some more reloading under my belt before purchasing. Your results will help me make up my mind. Good luck!

 

[stlaser]

Dustin is going to drop off that brass early next week. Hope to hear of some test results soon.......

 

[84VETTE]

I trimmed down some brass for my guide gun this summer. I haven't had a chance to work up any loads yet. I'm planning on using a longer bullet and not seating it as deep so the over all length is similar to the original 45-70. That should make figuring out a load simpler.

 

[UncleNorby]

Sounds like a good cartridge. Good luck with it. I know folks are doing something similar by just shortening the 45/70 to 1.800.

Also, I have wondered if anybody is looking at a "44 Maximum", as has been done with the 357 Mag. I'd imagine a 44 Mag case stretched to 1.800 would be a good round as well.

Does anyone know a lever gun chambered in 44 Mag that could cycle a round 0.175" longer than the standard 44 mag length? I realize the chamber would have to be reamed. Is this feasible? Thanks.

 

[Broom_jm]

I trimmed down some brass for my guide gun this summer. I haven't had a chance to work up any loads yet. I'm planning on using a longer bullet and not seating it as deep so the over all length is similar to the original 45-70. That should make figuring out a load simpler.

I think the difference here is that you had to trim roughly .300" of the 45/70 case, which is probably 75% of the area that would have gripped the bullet. When you trim a 35 Remington case .120", that's maybe 33% of the neck. So, a whole lot less brass removed and a whole lot easier to just seat the bullet long and use standard reloading data.

With the 45/70, you've lost a significant amount of capacity and really need to look at a slightly faster powder. If you just go to much longer bullets, your velocity is going to be way down and then I'm not sure you've gained much, in terms of effective range, over a slug gun.

It would be cool to see someone neck a shortened 45/70 case down to .358", but then you're talking custom reamer and dies, so a full-on wildcat. I imagine someone has done that, though I haven't heard of it, thus far.

 

[parkerj112]

Sub'ed for further info.

Parker