10mm AMT magnum Contender?

[mr.trooper]

I'm looking to build a short range deer carbine that can utilize most of the reloading components I already have.

I hand load for a 10mm and multiple 40 S&W pistols, AND my state require a minimum case length of 1.16".The 10mm magnum seems like the perfect round to meet the case length requirement while utilizing .400 bullets.

My questions are - what length of barrel should I have made, and what velocity could I safely reach in a long tube?

I notice that BBTI shows the 10mm auto loosing velocity after 14" in their contender barrel.

I also noticed that the lighter bullets tend to do better in long tubes across all pistol cartridges - Is this because of the slight increase in case capacity?

Since the 10mm Magnum has roughly 30% more case capacity, would an 18" barrel be too much? Furthermore, since the 10mm Mag easily reaches 1650fps with a 200gr in an 8" barrel, would it be unreasonable to expect 1900fps from a 16-18" carbine?

Again, my questions are:
1) What barrel length would be optimal?
2) What velocity can I expect from the increased capacity?

All input is appreciated.

 

[MachIVshooter]

I think you'd reach your velocity potential inside of 16", so might as well build the lightest and shortest rifle possible. And I think with the right powders, your velocity expectation is reasonable.

That said, the 10mm mag (which I have ammo for and am planning to build on a modified Tanfoglio) kinda loses it's appeal in a single shot application. IMO, you'd be better off with a .357 Maximum. It has more case capacity and better bullet selection, including spitzers. With 10mm, you're stuck with handgun bullets that are pushing their limits at 10mm mag pistol velocities, let alone another 200-300 FPS from a carbine. .400" 180 and 200 gr. bullets just weren't meant to hit things at 1,600+ FPS. I've even found that the 180's have shaky performance at hot 10mm velocities (1,400 FPS)

 

[mr.trooper]

357 maximum defeats the purpose.

Thank you for your input regarding barrel length, velocity, and bullet construction.

 

[MachIVshooter]

357 maximum defeats the purpose.

Not buying a $25 die set? Forgive me if that seems a silly reason to opt for the cartridge with less flexibility and potential.

If you just want a 10mm Mag, that's fine. I totally understand.

 

[kludge]

Bullets are cheap. Dies are cheap.

I looked at the 10mm Magnum for IN deer hunting as well, and a *bunch* of others. Unless you have a source for brass I can't see it. The only source I know of is Starline, and they are backordered until "sufficient backorder is achieved."

But I know the attraction of doing it your own way. I really wanted a .45 Win Mag -- and I wanted it semi auto. Not too many options out there -- not even custom, and not anywhere near where I was willing to pay. I still drool over the thought of a .30 Carbine converted to .45 Win Mag, or anything similar.

If you really want a .40 cal, there's always the .38-40, but it's performance is pretty anemic in factory loadings... Handloaded to it's potential it can get you up to ~1700fps+. It's funny that the .38-40 is legal and the 10mm is not. (The reason it is 1.16" is because it allows the 44 SPL, but not the .38 SPL.)

You could always do a wildcat... maybe you could take .45 Win Mag brass (.454 Casull or .45 Colt brass which is rimmed and would work nicely in a single shot) and neck it down with a .40 Super die or a or .400 CorBon die, but not trim the brass. Maybe it's already been done? Who knows. Then there's the .401 GNR. But then you have to wonder... even with the 10mm Magnum... is anyone making bullets suitable for deer hunting that will expand properly (not blow up) at 1800fps.

People are getting 2200-2300fps from the .357 Max in a 22-24" single shot with the 180gr Hornady SSP. Just take and ream out a $200 H&R Handi-Rifle. Done. I've also read about people reaming .45 Colt Handi's to .454 Casull... I've yet to figure out which frame they are using though.

I ended up going with a .358 WSSM -- a buddy who is a trophy hunter wanted a 300 yard deer rifle and paid for the "tooling", otherwise I'm sure I would have gone the .357 Max route (.35 Rem performance).

If the 1.8" rule is adopted the .357 Herrett and the .460 S&W will be legal, so a this point it might be wise to wait and see what happens with the 2012 deer rules.

 

[mr.trooper]

I realize the velocity would be very high at the muzzle, but don't forget that with BCs below .200, most 200 grain 40 cal pills would loose at least 400fps in the first 100 yards

I too have been seriously considering a 358 WSSM or 358 BFG. There are probably other options that exceed it in muzzle energy (like the 460 if it gets adopted), but nothing beats it for flat trajectory or retained energy beyond 200 yards.

Thanks for bringing up the 401 GNR - That has perked my interest! Can you tell me a bit more about it? (the website doesn't say much, and Google searches are futile thanks to "Guns and Roses")

I may end up playing it conservative, and just buying a nice slug gun, like the new A-bolt... but two things I know for sure - first that old smooth-bore has GOT to go, and a shiny new carbine is a VERY tempting proposition!

* EDIT*

I Just looked at brass. Midway has plenty of 10mm mag brass in stock, and it's actually a hair cheaper than 357 Max, and both are about 5 times cheaper than 357 Herrett brass.

 

[kludge]

Until I built my .358 WSSM I hunted with a 9.5" Super Redhawk in .454 Casull. It BLOWS AWAY my 1100 w/Hastings barrel slug gun for accuracy (can't keep it on a paper plate at 50 yards) and I refuse to pay $15-$20 for 5 rounds of fancy shotgun slugs. The .454 has more than enough ME for whitetail, and I can actually hit a whitail at over 100 yards with it. The .454 with 300gr XTP is equal or beats the .460 with 200gr FTX at longer range, so I never saw the advantage of spending almost twice as much on a gun. Without the .358 WSSM I'd rather be hunting with a 14" 7-30 Waters or .35 Rem. in a T/C, but I like the .45 Colt, so the .454 was a natural step up from a slug gun.

The .358 WSSM has more than enough ME too, 2700-2850 ft.lb., roughly the same as the .460S&W. But it can't match the retained energy of the .358 which is still at or above 1000 ft.lb. depending on the bullet out to 400 yards... but I consider that to be beyond it's capability from a trajectory standpoint.

I used the "Redding" version of the .358 WSSM, since their dies are off the shelf - no waiting 16 weeks for custom dies to be made. Manson made the reamer using the Redding print (just ask for the Redding compatible .358 WSSM), so you know it will all work together. Neck turning is required with this design though. If you add it up it'll be about $1200 (barrel, dies, donor rifle, reamer, gauges). Maybe under $1000 if you can rent a reamer and gauges. I did better than that due to my "benefactor". Like I said, he paid for all the tooling, and I did all the legwork. I'm in for ~$650, rifle and dies. If I had to do it again, I'd go for the .357 Max with 180gr SSP or 200gr FTX -- I was OK with a 200 yard rifle.

http://redding-reloading.com/images/stories/358-25prshot.jpg.

That's interesting about the brass. I couldn't find any a couple years ago when I began my search in earnest.

I know nothing more about the 401 GNR, just that it exists. If you like the 401 GNR, you might also like the .358 GNR for a single shot. It's based on the .445 Super Mag case (max legal length). http://shootersforum.com/showthread.htm?t=62945 If you search the same site you'll find my thread on the .358 WSSM.

Of course next year a .358 or .40 based on the .460 case will probably get the attention of some... but then so will a .358 based on the WSM case, which I project will approach or match .35 Whelen ballistics. I'm exceeding .358 Win factory load numbers (200gr Silver Tip) with the WSSM. It might be tempting... I've heard Dave Manson will regrind the reamer for $30... bah, what do I need .35 Whelen ballistics for? I'd rather have a .338-06.

One thing is for sure Indiana wildcatting is alive and well.

Sorry i'm so longwinded.

 

[mr.trooper]

No don't apologize! I need the information, and the discussion is helpful.

The 460 is indeed very tempting - the velocity figures I'm reading from people who have made 22" barrel 460 carbines would be generating WELL over 3K foot pounds.

That's all moot though, because even if those numbers are true, it would shed velocity so fast that the 358 WSSM would still surpass it in all areas once you go out past 200 yards.

My #1 priority is still maintaining component commonality with the trio of 40 S&W pistols and the pair of 10mm pistols that I already have... I DO have a 44 magnum, so cartridges using a .429" bullet or 44 mag brass would be OK as well.

The 10mm magnum and 401 GNR are both equally tempting to me at this point - i like that the 10 mag is so similar to the 10 auto, but the 401 GNR has the ability to use stronger and more common 44 mag brass for the same ballistics.

 

[kludge]

OK, for the .460 energy numbers I was assuming 2500fps from a rifle. I have seen some "claims" of 2800+ fps from a rifle... but I'm not buyin' it... yet.

.44 Mag... there you go... there's your cheap single shot, effective to maybe 150 yards or a bit more with some practice. More energy at 150 yards than a .357 (handgun) at the muzzle.