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10mm loading and testing

John A.

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I've been wanting a 357 lever gun for a while now, but can't find one in stock, and the ones I do find, are way over-priced so I've been thinking how to make a nice lightweight carbine that I can still use for a brush gun and to hunt whitetail with. And in comes the 10mm.

Since I'm wanting to hunt with it, I prefer to push the bullets as hard as I can.

Thankfully, I had some varying powders squirreled away that gave me the chance to try some different loadings to shake it out and see how it does.

Where I had the xd40, I had some 155 and 180 gr bullets that I could load and a die set. I'm currently going to order some various hard cast bullet profiles to see what I can come up with before deciding to get a bullet mold. Mainly to make sure they can handle the pressures and velocities that I want to run them, and of course, to make sure they feed reliably in my gun too.

But, here's the results of what I was getting from my first outing with it if anyone is interested.

The #9 powder with 155 gr xtp hornady was by far the most impressive speeds.

15.9 gr no. 9 powder
155 gr xtp
1.25" col

1748
1750
1780


1769 fps ave

1077 ft lbs
----------------------------------


155 gr xtp
7.2 gr titegroup
1.260" col

1511
1507
1504
1499
1483

1500 fps ave
774 ft lbs
-----------------------------------
155 gr xtp
9.4 gr Longshot
1.260" col

1609
1616
1555
1576
1554


1582 fps ave
861 ft lbs
---------------------------------------------

180 gr armscor flat tip
8.6 gr BE-86
1.255" col

1444
1448
error
1432
error

1441 fps ave
829 ft lbs
 
Oh YES, Accurate #9 is superb in the 10mm Auto. And it meters so well. And is flash suppressed. Your results don't come as any surprise to me.

Was that with a standard LPP or a magnum LPP?
 
To be perfectly honest, I've not found any new brass yet. A buddy of mine had picked up some blazer brass a long time ago that he gave to me to at least get me started until I could find some in stock somewhere, and they were small pistol primer pockets.

I didn't even know that SPP 10mm existed, but true enough, I have a couple handfuls of them.

I was using regular SPP's in them.
 
John, I will send you some once-fired brass if you will PM me (to remind me) your address. I think I've got quite enough and much of it has been tumbled.
 
Yeah, that is nice, but are you sure I can't pay you for it? Or trade something you may want/need?

What about a bunch of 380? Recently, my uncle let some of the people that goes to church where he does do the shooting portion of their CCW's at our private range.

I picked up several boxes of once fired up afterwards since they left it laying. I personally hate 380 and don't even own anything in that caliber, but you know how it is when you see a pile of brass. I picked it up anyway.

Would that do anything to help you any if you're interested in it?

Also have a bunch of different shotgun wads in 12 and 16 ga.

I'm just grasping at straws here, so if I don't have anything now, maybe I can return the favor sometime in the future? I don't foresee the times getting better anytime soon and I'm afraid we're going to be relying more on our friends and family going forward. Especially if things get really stupid and sideways.
 
Thank you buddy.

There's a few things I'm sure you know about me with as long as we've been friends.

I never forget when someone screws me over. I can hold a grudge like nobodys business.

But I also never forget when someone does me right either.

So, that goes both ways. The offer stands if there's something I can help you with. Now or later.

Thank you again !!!!!!!!!!!!!!!!
 
I've been wanting a 357 lever gun for a while now, but can't find one in stock, and the ones I do find, are way over-priced so I've been thinking how to make a nice lightweight carbine that I can still use for a brush gun and to hunt whitetail with. And in comes the 10mm.

John, just out of curiousity have you looked at any 10mm carbines instead of a 357 one? I've been looking and while I haven't seen a 10mm lever action there are 5 or 6 different offering in 10mm including:

  • Thureon Defense PCC
  • TNW Aero Survival Rifle
  • Hi-Point 1095
  • Kriss Vector CRB
  • Just Right Carbine Takedown
  • Olympic Arms K10
I been looking for something light weight and the TNW takedown offering looks interesting. The other issue I'm looking for is interchange compatability with Glock 10MM mags like used in my Glock 20. I havem't handled any of these weapons yet and unfortuantly, prices are all over the place these days.

Regards
 
That's essentially what I have done Ernst.

Sadly, Olympic Arms is now out of business so finding one of those would be pretty difficult. I was a moderator at the old olympic arms website for probably 15 years. I had a lot of good times on that forum and made a lot of good friends.

I actually used an old Olympic Arms freefloated handguard (FIRSH) on this project because I had one handy in my spare parts box and I didn't really have the extra cash to buy the handguard that I wanted right now. So, it'll do for the time being. Though I would appreciate one that is a more narrow profile.

Started out last year buying a paperweight and making it into what it is now. A survival and hunting tool.

It's a bit of a frankenstein project, but here's the parts list.

16" barrel from New Frontier Armory
40/10mm bolt carrier from KAW precision.
10oz buffer weight from KAW Precision.
308 caliber carbine buffer spring
pistol caliber stripped upper receiver from midway (was their ARstoner house brand)
45/10mm glock style Wolfpack receiver blank
unknown/mixed lower parts kit
6 position buffer tube and magpul stock.

Optic and all (no loaded mag) is very likely between 6 and 7 lbs (guessing) and is really pleasant and handy.

It took a while to find/get all the parts that I used. 40/10mm AR stuff is somewhat rare due to not as much interest in it for some reason from the market. 9mm and 45acp are probably the two most popular pistol calibers for AR's. But, if you're patient you can get everything you need to make one. I have between $500-$600 in it? I haven't added it up, but that's way cheaper than you can get a 357 lever action for right now and similar ballistics.

Yes, it uses glock mags. The New Frontier Armory and Wolfpack lowers both do. I'm assuming many other AR style lowers do as well, but I know for sure those two do. I just haven't really looked into that all that much or know who all is making fat glock mag lowers.
 
John, that build sounds interesting. Might look ay some of the components you used.

Thought you might find this velocity test info interesting. It's from the TNW web site comparing the same rounds shot from a Glock 20 and the TNW 10mm ASR. The ASR barrel is a 1:16 twist. Not sure how that twist rate compares with your New Frontier Armory barrel?

TNW Firearms_Velocity_10mm_PressRelease_sm.jpg
 
My testing so far has been limited to only a few powders and bullet weights, but this one is performing nearly the same from what handful of ammo I have shot through it. I only got the first few shots this week, so I haven't been able to work the loads up and try to tweak them to squeeze out a little more, but those velocities and bullet weights would hold their own against a 357 mag if comparing the two from ballisticsbytheinch. 155 and 158 gr bullets are close enough to say they're the same weight. And also looked at the buffalo bore 357 mag 180 gr bullets and the 180 gr loads I tested were both nearly the same. 357 was 1400 fps ave and 10mm was 1440 average and I haven't even tweaked them a little more. I'm sure I can squeeze a little more out of it before starting to see some pressure signs.

http://www.ballisticsbytheinch.com/10mm.html

http://www.ballisticsbytheinch.com/357mag.html

The 10mm that I just built is the bottom one. It looks like most any other AR15 pistol caliber. I'm pretty sure my barrel is also 1:16 twist. But it is a pencil diameter barrel and has a 5/8-24 twist muzzle threading. It's in the 6lb ballpark so would be very maneagable in the woods.

Hh7C2oP.jpg
 
I know that it's been a little while since I updated the topic, but I've been shooting the gun and really enjoying it. But, since you all know that I'm loading the rounds pretty spicy, as you would imagine, it's really ejecting the cases into the next zip code.

I'm using a brass catcher, but I've been trying to tone down the ejection somewhat anyway.

So far, I have tried a flat coil chrome silicone 308 caliber buffer spring. Which was actually worse than the 308 caliber round music wire spring I started with. Or, at least the flat coil one from Wilson Combat was. I have a suspicion that the rifle/carbine spring from Tubbs/Superior shooting has more coils and is longer and I'll probably be trying that in the near future.

Another thing I wanted to do was to use a rifle buffer tube. For starters, I like the length of pull better. And where it has a slightly extended movement, that may help as well.

BUT, you can't find a really heavy (10 oz) rifle buffer. Nobody makes them.

Well, not until tonight.

So, my solution is to use my 10 oz carbine buffer in it, but naturally, it wouldn't have been long enough if I hadn't made a 1.8" extension to add to the rear of it. I still need to make the sleeve to go over the buffer so the rifle buffer spring will seat in the right location, but you can use your imagination for that. I'm going to fabricate that tomorrow, but I think you'll be able to understand what I had in mind.

And since I added a little metal to it, it now weighs 11.6 ounces instead of 10oz. So, it gained a little weight, which may also help tone the ejection down a little more too.

I could even bore out the extension that I made and add at least 3 more buffer weights if I'm inclined as well. But, I'm going to try to avoid that if possible. I don't want the gun to weigh 13 pounds.

I guess I'm getting ahead of myself a little, but here's what I worked on after eating supper tonight.

I don't see a reason why it wouldn't work. I'm going to make a simple sleeve that will slide over the shaft and butt up against the head of the buffer so the spring will seat in the same place a rifle buffer spring does. But, that's going to be tomorrow evening.

HHelNo3.jpg


I have always liked the Ace/Doublestar style buttstocks with the foam on them. But, since I'm trying to save weight where I can, I'm going to rig up my own style of stock by using an A1/A2 buffer tube, the piece of foam, and since the aft is wanting to ban pistol braces and call them buttstocks, I'm going to mount an extra gear head works tailhook on it and use it similar to how the lightweight stock they have.

The stock will look similar to this externally. Not exactly, but similar. I got this image from a quick search for the ultralight stock. I'd give credit for whoever took the pic, but it was on armslist and I have no idea who it was.

iu
 
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