How long can I load 40S&W (OAL)?

[atblis]

The short of it
1)Bought a Glock 20
2)bought a Lone wolf 40 S&W conversion barrel.
3)Ran a 40 S&W case through my press (setup for 10mm). So basically I have a 40 S&W loaded to an OAL of 1.26"
4) 40S&W loaded to 1.26" drops in the chamber and as far as I can tell, does not touch the rifling.

I determined this by
A)noting that the round chambers freely and does not get stuck (can't wedge it into the rifling). Feels like it's spacing of the mouth of the case.
B) Jammed a bullet into the rifling measured to the crown. I did this for three different bullets and got 4.148", 4.144" and 4.144". I then put the 40 S&W loaded to 1.26" in to chamber and measured to the bullet and got 4.182".

SO by my calculations the bullet is seated ~0.035" away from the lands.
Looking at the chamber, it does look to have a long throat.

So what I am asking is does anybody see an issue with doing this?

My intent is load 40 S&W up to 10mm velocity and just simply use 40 brass rather than 10mm.

Just wondering if I am missing something before I go to the range tomorrow. Starting with 40 S&W data.

Thanks,
Andrew

 

[Casefull]

Andrew,
I have the exact same setup...pistol, lone wolf 40 barrel and it works great. BUT do not reload the 40sw to the oal of 10mm because your barrells chamber is for 40 mm length. I load my 40sw up to 1500 fps without problems BUT at 40sw length. You are asking for huge problems if your bullets are too close to the lands with a hot load. Many problems with pressure and damaged firearms are from exactly what you are talking about. You want that bullet to "get going" just a little before it hits the rifling. You will love the way it shoots the 40's.
Chuck

 

[D. Manley]

My intent is load 40 S&W up to 10mm velocity and just simply use 40 brass rather than 10mm.

Just wondering if I am missing something before I go to the range tomorrow. Starting with 40 S&W data.

Very bad idea. Much smaller (and likely weaker) case has less capacity equating to much higher pressures. Trying to make a 10MM out of a .40 is a recipe for trouble.

 

[nelson133]

Not only is it dangerous to overload the brass, you will need a cheap source of brass, as you won't get many reloads before failure. I hope for your sake the failures are cracked and split brass and not case head failures. We call those kabooms.

 

[jfh]

It's your gun, and your injuries. Long-loading such a case as the .40 S&W has no advantages that I can see. Will a 1.126 round feed from your magazines, or are you planning to use this as a single shot?

I no longer load .40S&W, but I do load 10mm and folllow the forums for that round. On another forum, an avid 10mm loader started pushing 135-gr. bullets as far as he could go. Extended discussion of his posts yielded the fact that his rounds were having first-wave pressure spikes of at least 55,000, and more likely 60,000 PSI.

Keep that in mind--and remember what the SAAMI pressure is for .40S&W.

edit: I see that this was a conversion barrel for a Glock 20--hence, your rounds should fit and feed OK. It's my error for missing that earlier. Nonethess, my observations still stand--and I'd call out the fact that, with your long-loading technique and the pressures you want to operate at, even +- 001. cartirdge LOA variations--not to mention Bullet LOA variations--will have BIG changes in that first wave pressure.

Incidentally, I blew up my Glock 20, and that was without hotrodding; it was a (lead) 200-gr LSWC over 4.9 gr. of 231, and it ran about 900 fps from a 6" Omega.

Jim H.

 

[atblis]

SAAMI pressures are
35k PSI for the 40
37.5k PSI for the 10mm

We're not talking a huge difference here.

Advantages of using 40 S&W brass

A) It's cheap/free.
B) Potentially stronger (Clark seems to think so based on destructive testing)

As a side note (not that most don't know this):
Comparing the Lone Wolf barrel to the Factory barrel, there is a huge difference in the way the chamber is cut. The slop in the factory Glock barrel is incredible.

 

[D. Manley]

SAAMI pressures are
35k PSI for the 40
37.5k PSI for the 10mm

We're not talking a hug difference here.

Advantages of using 40 S&W brass
A) It's cheap/free.
B) Potentially stronger (Clark seems to think so based on destructive testing)

As a side note (not that most don't know this):
Comparing the Lone Wolf barrel to the Factory barrel, there is a huge difference in the way the chamber is cut. The slop in the factory Glock barrel is incredible.

It's not going to work that way. Loading the smaller case to approach 10MM velocities will cause a large increase in chamber pressure. If you know someone with Quickload get them to run the numbers for you and I think you'll find the results of what you're considering can get scary really quick. If you want to load .40, no problem but you would be well advised to remain within .40 load specifications.

 

[atblis]

Yes but

Yes sure, but don't I have the same internal volumes if I load to 10mm OAL? Less of the case is taken up by bullet now.

 

[MikeRz]

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