Seating 9mm out to 38 super COL

[RWatts]

So I recently had a well know pistol smith (in this area) suggest that I load my 9mm out to 38 super COL. He believed this would result in better reliability. (STI edge) but also said this would allow for the removal of the spacer in the mags. So my questions are. 1. What do you guys think, have any of you tried it? 2. Is there enough throat for this, I believe 9mm head spaces off the case mouth, so that shouldn't be a problem but will I be jamming it in the lands(rifle terms not sure if it applies here). I'm using xtreme 135 hp's and 3.4 titegroup.

[al503]

I load my 147 grain RN x-treme loads out to 1.245" and 135 grain RNFP x-tremes out to 1.2" At those lengths, there is no issue with setback. No issues with reliability out of SV mags.

Whether your barrel has enough throat/freebore is anyone's guess. I would load up your 135's out to something around 1.23" and do the plunk test with your barrel. Keep reducing your OAL until you get a nice 'plunk.' (Make sure the chamber is clean.) After you get that length, chamber that round at least a few times and see if the OAL stays the same or you're getting setback.

Its my understanding that its not the OAL but that the spacer pushes the case forward enough so that the case rim contacts the magazine's ribs on STI tubes. Some report no issues without spacers and some report the opposite.

[Hi-Power Jack]

For loading 9mm Major, we've been loading as long as possible for many years.

As AL503 mentioned, run the Plunk Test in Your Chamber and see how long

your chamber & mags will run. No disadvantage to loading long = but some

advantages. You'll need to run The Plunk Test for each bullet type you use.

Make sure you don't load so long that you don't have sufficient bullet inside

the case to get a firm grip on the bullet.

I talked to the people at Brazos and they said my SV mags would not require

spacers if I loaded long - but I load to 1.145 - 1.17" - any longer and the bullets

don't stay in the case. I've never been able to load MG 124 gr JHP's

out past 1.17" reliably.

My STI mags require spacers even at 1.165".

Edited May 26, 2015 by Hi-Power Jack

[RWatts]

Thanks for the replys, could someone explain the difference between the STI/SVI mags? I thought they were the same.

[yoshidaex]

SV mags have one wide rib running the length of the mag.

STI mags have 2 ribs running the length of the mag.

[RWatts]

And that changes how the mag functions because....?

[racknrider]

Don't forget to chrono. You're gonna need more powder when you load longer.

[Glk21C]

Its my understanding that its not the OAL but that the spacer pushes the case forward enough so that the case rim contacts the magazine's ribs on STI tubes. Some report no issues without spacers and some report the opposite.

"And that changes how the mag functions because....? "

If the case contacts the rear edge of the most forward control rib, you can have feeding problems within the tube. For 100% reliability use spacers for 9mm in an STI mag.

[al503]

And that changes how the mag functions because....?

The rib(SV) or ribs (STI) that run down the sides of the mag just keep the rounds from binding side by side. I don't have any mags in front of me but the ribs that matter in feeding are at the lip of the mag. They make sure that that round is pointed correctly for the feed ramp.

Again, without them in front of me and as I understand it, the STI's ribs are out a little further than the SV's so they make contact with the bullet and not the case. The difference is minimal but that could lead to a round that isn't pointed where it should be.

Hope I made sense.

[RWatts]

ok so im not trying to be a PITA but, how will the mag know the difference between a 38 super and a 9mm seated at 38super COL? You dont run a spacer with a 38 super... Just trying to understand what the difference is.

[RWatts]

I have read about the plunk test and will do this, i will be shooting for a 1.2 OAL and see how it goes...lol i believe in match testing everything...

[al503]

ok so im not trying to be a PITA but, how will the mag know the difference between a 38 super and a 9mm seated at 38super COL? You dont run a spacer with a 38 super... Just trying to understand what the difference is.

It's where the feed ribs touch the round that matters. Without a spacer, the ribs hit the bullet (there's going to be some slop), not the brass (which is wider).

Try this: load a 9mm round into the sti mag without a spacer. You'll probably be able to wiggle the nose of the bullet side to side. Now push the bullet forward about the width of a spacer and try to wiggle it again. It should wiggle a lot less.

Edited May 26, 2015 by al503

[Hi-Power Jack]

i will be shooting for a 1.2 OAL i believe in match testing everything...

Try it, and I may be wrong, but I don't think you'll be able to go

that long in a 9mm ...

I've standardized at 1.165", but have gone out to 1.175" (didn't

like to load that long, since I felt I didn't have enough grip on

the bullet in the case).

[BeerBaron]

ok so im not trying to be a PITA but, how will the mag know the difference between a 38 super and a 9mm seated at 38super COL? You dont run a spacer with a 38 super... Just trying to understand what the difference is.

One thing to consider is the 9mm is tapered. So as it comes up the last bit of the mag where it's single file it can tend to nose down a little.