Can a 10mm SA be modified to shoot .40 S&W ?


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VE2RF
June 24, 2008, 02:29 AM
I really like 10mm guns, but they're still really impractical for me to own because the price of 10mm ammunition remains so high.

I taken a look at a Dan Wesson Razorback 10mm and I really liked everything about it. I had made up my mind to buy it, but looking at 10mm ammo prices put a quietus on that purchase.

Oddly enough, a gentleman was at the Uchee shooting range last week, and I was admiring his Colt Delta Elite 10mm, when I noticed he was shooting factory .40S&W ammo. I asked him about this and he stated that it was a cheap conversion to get a 10mm to shoot .40 S&W

He commented that in his pistol's case it was matter of a lighter recoil spring, tuning the firing pin to avoid piercing the .40 S&W primers, and machining to get the gun to feed.

I didn't feel comfortable trying to root out the nitty gritty details as I really didn't know the man, but having found this deal on a Razorback 10mm I thought I would ask.


To the best of my knowledge the .40S&W is shorter than 10mm, so how do you properly make a 10mm shoot .40 S&W ? Rebarrel with a barrel with a shorter chamber ?

I know the cheapest answer is to buy a .40 S&W caliber gun in the first place, but whoever said that's any fun ?

Thank you.

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freakshow10mm
June 24, 2008, 02:37 AM
Do not fire a 40 S&W in a 10mm chamber. Don't go there.

Just get a 40 S&W barrel for your 1911. Problem solved.

DragonFire
June 24, 2008, 09:09 AM
I didn't think it was possible to use a 40 in a 10mm barrel. I would think that at best accuracy would suffer as would reliablility. It's not something I would do.

I have a DW RazorBack and bought a .40S&W barrel for it.

The rounds fired fine and overall the gun was pretty accurate, but I had a problem with extraction. I encountered alot of jams because the 40 cases weren't extracted/ejected before the next round tried to load.

I solved it (after alot of advice from a much more knowledgable friend) by also using a reduce-power spring, and using only dedicated brass. What I mean is that I only use factory new or reloaded brass that has been fired only in this gun.

Since I've done that, I have no few if any problems.

burningsquirrels
June 24, 2008, 09:15 AM
the 40sw is basically a shortened 10mm. a different barrel will do it for you. also, you will probably need a recoil spring since the 40sw can be significantly weaker than the 10mm depending on what the difference is in ammo you use in 10mm and 40sw.

sqlbullet
June 24, 2008, 03:20 PM
A little more of a deep dive reveals two specific safety issues with this practice.

First, the extractor probably is not strong enough to properly hold the case when it is struck by the firing pin. This will move the case forward in the chamber. This may result in a light strike and failure to fire. More dangerously, if the firing pin reaches far enough (many do) the cartridge will fire without the support of the breech face. The primer may fail or be blown out, resulting in hot gas being vented into the breech. There are some really ugly photos of 40 S&W brass after fired in a 10mm chamber.

The second potential issue is copper or lead fouling of the chamber shoulder since the case mouth may not engage this shoulder correctly. When returning to 10mm ammo, this extra material could act as a wedge against a 10mm cartridge, increasing the pressure when more force is needed to break the bullet free from the crimp.

The only solution is to get a 40 S&W barrel. A recoil spring may or may not be needed. While I am spending your money on barrels, go ahead and get a 357 sig and a 9X25 barrel too.

Quiet
June 24, 2008, 05:18 PM
Do not shoot .40S&W out of a 10mmAuto pistol.
You need to get a .40S&W replacment barrel before you can safely do so.

I really like 10mm guns, but they're still really impractical for me to own because the price of 10mm ammunition remains so high.
I believe it's a requirement for all 10mmAuto shooters to reload. :p

10X
June 24, 2008, 06:29 PM
You would have to get a 40 S&W barrel for the gun and get it fitted properly. $150-$200 for the barrel plus fitting, if you know of a competent gunsmith that really can do that. It is a bit of a gamble that the gun will work right.

The 10mm mags may or may not work. You might have to get 40 S&W mags to prevent the rounds from riding forward under recoil. More expense.

With the conversion your gun would no longer be original, so, its value is reduced. Instead of having of having a 10mm (a bit exotic or niche or cult gun) you would have some mickey mouse conversion.

This could be done, however, I would not call this a cheap conversion. If it were me, I would put this money in 10mm ammo and not look back.

Dr. Tad Hussein Winslow
June 24, 2008, 09:29 PM
It will work but it's not a good idea - the round will headspace on the extractor, but you can get duds (light primer strike) and notsogood accuracy.

If it were me, I would put this money in 10mm ammo and not look back.

Yup, don't "dumb down" a fine weapon to a lesser caliber - .40 is not *that* much cheaper, is it?

atblis
June 24, 2008, 09:40 PM
40S&W brass is pretty much free. That's the allure of converting to 40S&W.

Get a new barrel.

Load your 40S&W long. No need for special mags or anything

With the conversion your gun would no longer be original, so, its value is reduced. Instead of having of having a 10mm (a bit exotic or niche or cult gun) you would have some mickey mouse conversion.
Having a drop in barrel wouldn't be a permanent alteration. Wouldn't hurt the value in the least.

Logan5
June 25, 2008, 12:23 AM
I had a Colt Elite 10/40 for a while, and never ran into any problems before I sold it (yes, to my everlasting regret.) The swap involved separate .40 and 10mm barrels and magazines, I think there were separate recoil spring assemblies, too. IIRC it was a real pain closing the old blue plastic hard case with all that in there.

Anyway, it sounds like you want a 10mm, not a .40 S&W... Go get it! Nobody's making you buy ammo more than one box at a time, and it's not that bad. It's not the end of the world to go buy what you want just because you want it on this one.

loop
June 25, 2008, 07:33 AM
The .40 S&W is merely a 10mm that is shorter in OAL. While it may be possible to shoot 40 in a 10 barrel it would be extremely ill-advised.

Both rounds headspace on the case mouth. That means the barrel determines how far the cartridge case will insert into the chamber. Due to the design of the 1911 the extractor holds the rim and may hold the case of the 40 well enough to fire the round, but it is very unsound mechanically.

To convert from 10mm to .40 requires a barrel, possibly a recoil spring (depending on the original spring, the loads you are shooting and numerous factors involving the gun) and the appropriate magazines.

You can buy a Lee Anniversary reloading kit for less than the cost of the barrel alone. For the price of springs and mags you can buy bullets, primers and powder. Then you can reload your 10mm for less than half the price of .40 ammo.

Don't waste your time or money on a .40 conversion. Reloading a 10 can give you many times the options of buying .40 in a box.

Your 10 will fire a 180-grain JHP at 800 fps. It will also fire a 200-grain lead cast bullet at 1,400 fps. Only you can make that happen. It starts when you decide to roll your own.

moooose102
June 25, 2008, 07:55 AM
i know the price of 10mm ammo is rediculous, just like .22 mag ammo is. is there a reason you do not want to reload? that is where the ammo costs really get better, and you could produce downloaded (less powerfull) full length 10mm ammo (reduced down to 40 s&w, or lower) any time you wanted. i routinely do this with my 300 win mag, and i am going to start doing this with my 45/70, 40 s&w, 45acp (more to make sure i dont lead the barrel with cast bullets) simply for more fun/less pain while practicing. there is also a small savings on costs (less powder) when doing reduced loads. but that savings is very small. but you can reload a box of your 10mm shells for less than 1/2 price of 40 s&w ammo. it does not cost all that much to get started, so think about it, IF YOU HAVE THE TIME, you can save some serious coin, at least if you do much shooting. also, that way, you dont have to buy separate barrel to shoot 40 s&w ammo. you still may end up buying a recoil spring, as the reduced loads may not provide enough power to run the action. but springs are way cheaper than barrels. and actually, you may be able to buy the reloading equipment for close to the same price as the barrel. god luck with your decision, and just GO FOR IT MAN!

10X
June 25, 2008, 11:02 AM
atblis, if the barrel is drop in, sure, it would not be a permanent alteration of the gun. 1911 barrels usually require some fitting, if only the new barrel or bushings are altered then fine. Too many hackers (pseudo gun smiths) start messing up guns when "fitting" barrels. Then you have a mickey mouse conversion. I have seen that too much and walk away from those "custom" guns that are messed up.

R&J
June 25, 2008, 07:25 PM
Consider Glock...

A G20 is easily converted to .40 S&W with a KKM Conversion Barrel and magazines.

A G21 and G30 can easily be converted to 10 mm in the same way.

.40 S&W is just barely cheaper than .45 ACP.

The conversions should work with the new SF series.

Far from Disney-quality conversions, these work and do not de-value the original firearm. A little tweaking with ammo types might be required.

http://www.kkmprecision.com/custom_pistol_barrels/home.php?cat=1

--Ray

Mortech
June 25, 2008, 07:33 PM
I'm trying to figure out why everyone else is saying 10MM ammo is ridiculously priced , for example I can get it a Sportco for the same price as 40S&W and 45ACP , all of which is retailing for about $14 /box of 50 around here .

atblis
June 25, 2008, 08:51 PM
It's more like $25-$30 around me.

R&J
June 25, 2008, 09:00 PM
I'm trying to figure out why everyone else is saying 10MM ammo is ridiculously priced , for example I can get it a Sportco for the same price as 40S&W and 45ACP , all of which is retailing for about $14 /box of 50 around here .

Yes, but most of it is watered down, falling far short of the true 10 mm experience.

For real .357 magnum performance in an autoloader, look to Double Tap:

Lets look at Double Tap .357 Magnum & 10 mm...

1) .357 Magnum, 1600 fps, 710 ft. lbs., 125 gr Gold Dot

2) 10 mm, 1600 fps, 767 ft. lbs., 135 gr Nosler **

3) .357 Magnum, 1400 fps, 688 ft. lbs., 158 gr Gold Dot

4) 10mm, 1475 fps, 750 ft. lbs, 155 gr Gold Dot

5) .357 Magnum, 1200 fps, 640 ft. lbs., 200 gr Hardcast

6) 10mm, 1300 fps, 750 ft. lbs., 200 gr Hardcast

http://www.doubletapammo.com/php/catalog/index.php?cPath=25

** My personal favorite!

--Ray

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