Got the 357 Sig reloads to work

[DownInTheDark]

I bought a Glock 32 a month or so back, and started working up some loads for it with used brass. Started with 14 grs of aa#9 shooting a 124 gr XTP. They came in at 1440 fps (avg). Max load was 14.6 gr which were going 1480 fps but were flattening the primer, so I have stuck with 14 gr. (might bump up to 14.2 later)

The only problem was the reloads weren't getting the slide to go back into battery. So I measured how far factory ammo stuck out of the chamber, and how far for the factory ammo. The difference was .007 of an inch. So I took a file to the case holder and took off .008 of an inch, which pushed back the shoulder .008 of an inch.

The gun cycles flawlessly now, and I am pushing a 124 gr bullet 1440 fps out of a 4 inch barrel. Cant complain.

 

[JimKirk]

My 357 SIG data does not go that high .... Where are you getting your data?

14 GRS should be max with 115 gr bullets.... Maybe 13.5 GRS. with 124 GRS bullets....

You should be using you barrel for a case gauge .... Called the plunk test ....Take the barrel out of the gun ....

My suggestion is to back off the load to 13.0 GRS .....

 

[DownInTheDark]

speer says 14.6 gr max with their 124 gr bullet. figure an xtp is close enough and started at 14. I used my barrel as a case gauge. I did the plunk test.

 

[JimKirk]

You should not have to move the shoulder back no more than a couple thousands ... at .008 you will have short brass life especially at Max loads like you are shooting .... I don't have a Speer book but I have several other reloading manuals and none of them go over 13.5 grs for a 115 gr bullets ... 124/125 gr are all listed at 13.0 .... You have to know that Speer was testing "their" gun ... it may and probably is not the exact same as your gun ... if you are getting OK loads at 14 grs ...and flattening at 14.6 grs .... I would back off until their was no flattening ... or stay at 14.0 gr ....

I load a Glock 31 and have for about ten years now without any problems like this ... How long are you seating the bullets C.O.L. ? I have shot a lot of AA#9 with the XTP bullets ....

 

[DownInTheDark]

OAL of 1.135

 

[JimKirk]

Good ....
Just so you know both of those bullets are "plated" and different than the XTP...

 

[vaalpens]

The velocity you are getting is higher than what is listed in the Speer manual (1480fps vs 1437fps). This should have told you something. It also looks like you loaded the XTP with a COL of 1.135", which is what is listed for the GDHP bullet in the Speer manual. I can't guarantee that my records are correct, but it shows that the GDHP bullet is about .5370" long, where the XTP is about .5750" long. This means that you were seating your XTP bullet about .038" deeper than the GDHP bullet, at the maximum 14.6gr, which obviously increased the pressure. Follow JimKirk's suggestion and start at the lower charge and work your way up. Be safe.

 

[DownInTheDark]

I already worked my way up, but thanks