9mm Major load for an Open STI with Comp!?

[jayjay1]

Hi guys,

a buddy of mine has a new Open STI in 9mm Luger with Comp.

Now he asked me, if I can find a load to make major.

I have never done a 9mm Luger Major load and have no experiences with Comps - but I´m reloading for over ten years now - so I´m not a totally newbie, only in this subject.

Would you give me some datas for this, especially to reach Major and activate the Comp?

Help wanted.

[Durtarg]

It largely depends on the comp itself and what will make it effective.

I run a Trubor T1 comp with 1 popple hole on my 9mm

Load data is

8.0gr of 3N37 @1.165oal with a 124gr MG JHP

I've also loaded using 7.6gr of Autocomp

I do run a minor load of 6.0gr of Autocomp for steel matches too.

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[superdude]

What gunpowders do you have? Compensators deflect gas. The more gas they deflect, the more efficient they are. Powders that require a large charge weight are generally favored because they produce lots of gas. Just to be clear, the compensator will be "activated" by any amount of any gunpowder. They don't have valves that require a particular pressure threshold before they start to work.

In general, a medium to slow powder is best, with the slow powders providing more gas for the compensator. Also, slow powders generally produce less chamber pressure than medium burning rate powders for the same velocity, while at the same time producing more gas (possibly muzzle pressure) for the compensator. See the link below for more detailed information.

http://www.shootingtimes.com/2014/04/09/compensators-pressure-gas/

9 Major is a little tricky because the 9mm cartridge does not have much case volume, and if you limit loads to around normal 9mm Luger length, the pressure with most powders can be really, really high. Some folks load their 9mm ammo long, but the length of the chamber's throat will determine how long it can be loaded. If the throat is long enough, the 9mm can be loaded as long as a 38 Super.

[jcc7x7]

Autocomp and it does not appear to be squirrelly as you increase the charge. At least in my guns

[Sarge]

8.0gr of 3N37 @1.165oal with a 124gr MG JHP

I've also loaded using 7.6gr of Autocomp

Dang! That's a lot of Autocomp! I run 7.3 with 121's at 1.168 and get 175 PF. 7.6 is what most guys run with 115's.

[Durtarg]

I ran 7.3 before I added the extra hole. So that was my load. I did change to the 3N37 because of the charge weight of Autocomp. Now it runs flatter and tracks extremely well at my current load.

I still use Autocomp for minor loads. It's an outstanding powder for 9mm

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[Sarge]

I ran 7.3 before I added the extra hole. So that was my load. I did change to the 3N37 because of the charge weight of Autocomp. Now it runs flatter and tracks extremely well at my current load.

I still use Autocomp for minor loads. It's an outstanding powder for 9mm

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Ah, I missed the hole.

[a matt]

Hey guy I have a Trubor just now setting up my load for 9major with Autocomp then I'll do 3n37. But my question is crimp I'm looking at about .380 to .381 wanting to make sure that's in the park? Also if I run them tru station 1 de-prime and size on my 550RL it seems to size my brass a little to much like .377. Any ideas on that issue. thanks in advance.

Durtarg, do you remember your 3n37 load before the popple hole was cut? Thanks

Edited June 24, 2014 by a matt

[superdude]

a matt, the undersizing (.377) is a good thing. It will help to maintain neck tension on the bullet to reduce/prevent setback during feeding. You might notice that your loaded rounds have a "coke bottle" look, with a narrow waist and wider at the base and where the bullet is in the neck. That's good. That's what you want.

Crimp for 9mm is hard to define in terms of .381 or .380 because brass thickness in this caliber can vary wildly. The metric often cited is that the crimp should be -0.001 to -0.002 less than the neck measurement. Some folks suggest no crimp, to simply remove the bell, so the crimp would measure 0.000. Any of those work fine with sufficient neck tension.

[a matt]

Superdude, you just described exactly what my case looks like. Thank you for the insight, cheers

Edited June 24, 2014 by a matt

[kneelingatlas]

Jayjay, am I correct in thinking you're not in the US? If that's the case, see if you can get some SP2, it really is pretty great for 9 major. I use 9.3gr under a 115gr bullet which is pretty sweet. Also, if you're shooting IPSC the minimum bullet weight for major is 120gr (112gr for USPSA).

[jayjay1]

Oh my gosh!

What a bunch of help and infos inhere, guys, you are fantabulous!!!

Thanks guys, with this infos (and Quick Load) I can work with.

@kneelingatlas:

I can get 3N37, HS 6, Auto Comp or SP2 here without any problem.

Powder is a little rare, but when waiting 2 - 4 weeks you can get almost any powder here when ordered.

I´m from Germany, still not belonging to the U.S., but we´ll see what comes.

So yes, good tip there, 124gr. is very common, so I would prefer loads in that bullet range.

Because of the OAL I must take a look what works in this pistol with the chosen bullet.

Question:

Can I only use jacketed bullets with the comp, because of the abrasion?

[Sarge]

Coke bottle is pretty normal in 9mm. .380 seems kind of wide. I generally crimp .376-.378 or so.

[Sarge]

Oh my gosh!

What a bunch of help and infos inhere, guys, you are fantabulous!!!

Thanks guys, with this infos (and Quick Load) I can work with.

@kneelingatlas:

I can get 3N37, HS 6, Auto Comp or SP2 here without any problem.

Powder is a little rare, but when waiting 2 - 4 weeks you can get almost any powder here when ordered.

I´m from Germany, still not belonging to the U.S., but we´ll see what comes.

So yes, good tip there, 124gr. is very common, so I would prefer loads in that bullet range.

Because of the OAL I must take a look what works in this pistol with the chosen bullet.

Question:

Can I only use jacketed bullets with the comp, because of the abrasion?

I only run jacketed so far in my 9 but some guys are reporting the new coatings on BBI, Bayou, etc are holding up well at open velocities. Also EXTREME plated says they will run up to 1500fps and some use them. They are another bullet on my list to try some day.

[kneelingatlas]

I use nothing but Xtreme plated bullets and I've done 1650fps with them.

[a matt]

I know my teammates at Rainier Ballistics are making major with 115gn w/o issue and accuracy is spot on as well.

I'm mainly a limited shooter.. I have not shot open so I figure I'll give it a shot at our local matches.

[a matt]

Coke bottle is pretty normal in 9mm. .380 seems kind of wide. I generally crimp .376-.378 or so.

Believe it or not . 377 is where I stop last night before finding this topic. Thank you all for your info, really good stuff. I'll get some chrono runs and accuracy runs down and join you folk again with some of my info.

Edited June 24, 2014 by a matt

[jayjay1]

The 9mm Luger, as the .40 S&W or the .45 ACP, and a lot of other pistol calibers, are fixed in the chamber with the case mouth.

So think about what you are doing here, when you crimp that!?!

What could happen is, that the case mouth stucks into the barrel, so that the bullet is fixed in the case,..... KABOOOM!

No sir, don´t want that.

What I do is measuring the case dia round about 1/4 of an inch behind the case mouth, when the bullet sits inthere.

That´s what I do "crimp", just tappering the case mouth lightly, laying it onto the bullet (like a straight cylinder).

Tapper crimp die is a must at all pistol calibers.

Coke bottle, well, the Dillon sizing dies are very thight, the tightest ones on the market I suppose.

I don´t see a benefit for that, especially not for Major loads in such a small case as the 9mm Luger is.

[a matt]

Well Here is what i have 7.6gr of 3n37 is my top but I'm starting at 7.1 of same. OAL 1.165 with a straight no crimp. Even at 8.0 the case is getting full but still not compressed.

[Sarge]

The 9mm Luger, as the .40 S&W or the .45 ACP, and a lot of other pistol calibers, are fixed in the chamber with the case mouth.

So think about what you are doing here, when you crimp that!?!

What could happen is, that the case mouth stucks into the barrel, so that the bullet is fixed in the case,..... KABOOOM!

No sir, don´t want that.

What I do is measuring the case dia round about 1/4 of an inch behind the case mouth, when the bullet sits inthere.

That´s what I do "crimp", just tappering the case mouth lightly, laying it onto the bullet (like a straight cylinder).

Tapper crimp die is a must at all pistol calibers.

Coke bottle, well, the Dillon sizing dies are very thight, the tightest ones on the market I suppose.

I don´t see a benefit for that, especially not for Major loads in such a small case as the 9mm Luger is.

.376 is nowhere near too much crimp. There is still plenty of case mouth there for chambering. Basically .376ish is just removing the bell. Staying out around .380 or more is asking for the mother of all jams when that round gets forced into the chamber!

[jayjay1]

.376 is nowhere near too much crimp. There is still plenty of case mouth there for chambering. Basically .376ish is just removing the bell. Staying out around .380 or more is asking for the mother of all jams when that round gets forced into the chamber!

Well, but the chamber is clean after some tries.

Sorry that I don´t know the inch measurements, I´m running in mm.

[Aircooled6racer]

Hello: 7.6 grains of 3N37 is not going to make major. It will be more like 140-150PF even with a 124 grain bullet. You are going to be in the high 8 grain to 9.1grains for a 115 grain bullet. I like Auto Comp a lot better than 3N37. 3N37 burns hot and is hard on the hand with more muzzle flip. It also does some weird dot tracking at 175-180PF loads. If you have it, use it until you can find some better powders for major 9mm. Thanks, Eric

[a matt]

Thanks Eric, looks like starting at 8.5 and moving up.

[Aircooled6racer]

a matt: No problem. Just watch the heat on the barrel you don't want to burn your hands after a 32 round stage. I will be at River Bend Gun Club this weekend if you want to try some Auto Comp loads. Thanks, Eric

[a matt]

That's super cool of you to offer but I'm a little to far south to make it up that way. But let me ask, what do you think about USPSA clubs ans shooting in general around Atlanta? I hope your move has been for the good.