OAL impact on power factor

[fowlh339]

First sorry if there is already a topic on this but I have read everything I can find and am still confused.

I am trying to work up a 9mm major load for my new Matt Cheely open gun. (A side not his service is impecable and the gun is awesome)

He recommended:

121 or 124gr Montana Gold hollow point. (I went with 124gr)

Around 7.8-8.0 grs of 3N37. 1.170 OAL

Small Rifle Primers

Here is the problem. I started at 7.8 and worked up from there. It wasnt until I got to 8.2 grs of powder before i broke 1350 FPS to barely make major. BUT I am flattening my primers to get there. I would work up 10-15 rounds and try them out and average then increase try again. On the last batch I noticed I got about 4 out of 15 rounds were ~900fps not 1350 fps. I assumed it was a fluke or bad reading but I read this can be due to insufficient crimp.

Please help. Could it be the crimp? OAL to long at 1.170? Will shortening the round help or hurt?

I would like to try and make this powder and bullet combo work as I bought alot of both...I know I am an idiot I should have worked out a round before buying +3000 bullets and 8 lbs of powder.

Any assistance would be much appreciated

using a dillon 650xl with dillon dies.

Edited August 14, 2012 by fowlh339

[yoshidaex]

You could go to 1.16 if it cycles fine in your gun.

The shortening of the OAL may bump up the velocities but I'm not sure how much it will come up.

For your last batch, double check your charge weights. 900fps for 8.2 grains is fairly low.

[Hi-Power Jack]

He recommended:

124gr MontMG JHP

Around 7.8-8.0 grs of 3N37. 1.170 OAL

Small Rifle Primers

It wasnt until 8.2 grs of powder before i broke 1350 FPS to barely make major. BUT I am flattening my primers.

On the last batch I noticed I got about 4 out of 15 rounds were ~900fps not 1350 fps. I read this can be due to insufficient crimp.

Could it be the crimp? OAL to long at 1.170?

Fowl, don't panic - shouldn't be a problem. You'll be able to use all the bullets & primers.

1. the 4/15 low velocity rounds - could have been a chrono error, or your powder charge wasn't correct

2. you don't need a crimp at all - just enough to remove the belling - shouldn't cause that problem

3. 1.17" is fine - I use 1.16", but I've used 1.17 and 1.18" in the past - all good. If you shorten

the load, you could get higher velocities.

4. Most importantly, I'd check how you measure the weight of the powder charge. Are you loading

5 charges onto the pan, weighing them all, and dividing by 5 to get an average? Good way to

do it - you might be loading less powder than you think you are. After you adjust the measure,

run 5-6 loads thru and throw them back in the powder measure - then load 5 and weigh them.

5. I'd check with Matt, who recommended the load - see what he says about this.

6. Primers will flatten on a 9mm major - with any powder, and any bullet - you are "on the edge"

loading 9mm to major - have to see photos to see if you're on the "ragged edge".

Good luck,

Edited August 13, 2012 by Hi-Power Jack

[fowlh339]

Thanks Hi-Power

I will take a pic of the brass tonight and post a pic.

As far as measuring powder I did not average samples. I just measure a charge (on beam and digital scale) adjust drop 3-4 charges then measure the 5th again. I will try and average a few samples this evening as well.

[lcs]

First sorry if there is already a topic on this but I have read everything I can find and am still confused.

I am trying to work up a 9mm major load for my new Matt Cheely open gun. (A side not his service is impecable and the gun is awesome)

He recommended:

121 or 124gr Montana Gold hollow point. (I went with 124gr)

Around 7.8-8.0 grs of 3N37. 1.170 OAL

Small Rifle Primers

Here is the problem. I started at 7.8 and worked up from there. It wasnt until I got to 8.2 grs of powder before i broke 1350 FPS to barely make major. BUT I am flattening my primers to get there. I would work up 10-15 rounds and try them out and average then increase try again. On the last batch I noticed I got about 4 out of 15 rounds were ~900fps not 1350 fps. I assumed it was a fluke or bad reading but I read this can be due to insufficient crimp.

Please help. Could it be the crimp? OAL to long at 1.170? Will shortening the round help or hurt?

I would like to try and make this powder and bullet combo work as I bought alot of both...I know I am an idiot I should have worked out a round before buying +3000 bullets and 8 lbs of powder.

Any assistance would be much appreciated

using a dillon 650xl with dillon dies.

I use a 650 and have loaded 9 major for years. Now shoot 38S so I have a lot of experience with both. 3N37 either works or it doesn't in 9 Major guns. 3N37 is also a high pressure powder as you can see from your primers.

The 124gn bullet is great choice for open. 3N37 ?? in 9 Major.-not so great. Barrel speed is also a big factor in 9 Major.

I will be glad to help as I went through the same things when I first started. PM or email me.

Larry

[Sarge]

PM inbound. I run a Cheely Open as well and I can help.

[G-ManBart]

Shortening your OAL can lead to an increase in velocity, but it can also lead to a non-linear jump in pressure. Sometimes that jump can be dangerous. Set the OAL to make the gun cycle reliably, then find the powder and charge required to make PF. Keep in mind these are generally reloading basics, and many people trying to load 9 Major really shouldn't be (no offense). It's pretty marginal in any normal combination people use (probably excepting SP-2 which is no longer available here), and it requires extra care to be done safely....and even then, I've seen bad things happen to some of the most experienced people using it. Also know that 3N37 puts heat into the gun at a very rapid rate. If you're shooting drills, it will get the gun hot enough to start premature barrel wear pretty quickly....I would run more than maybe two or three mags before letting it cool while you tape targets, reload mags etc.

Throw 10 charges into the pan, weigh, and divide by 10...that'll give you a decent average. Do three strings of 10 after you think you have it set. I find the first charge or three can be slightly off after making a tweak on Dillon powder measures so I dump them back in the measure before starting a new 10. 3N37 measures extremely well, so you shouldn't see big swings in charge weight. R,

[fowlh339]

I added pics to the original post. Is this normal flattening of primer or to much?

[yoshidaex]

That looks well within reason

[EkuJustice]

those look normal

[GrumpyOne]

Trust me, those ain't flat......they look fine, some pressure sign, but not enough to worry about.

[lcs]

Trust me, those ain't flat......they look fine, some pressure sign, but not enough to worry about.

FIRST picture--Third case in---look fine ????????? Not to me.

[Steve RA]

The primers look OK, if they are "flattened" the corners will be square, those are still nicely rounded. Also, all small rifle primers are not equal, some primer cups will be thicker than others and/or be different metalurgy/hardness. In my opinion, Remington 71/2 are the toughest and they get "softer" from there.

[GrumpyOne]

Trust me, those ain't flat......they look fine, some pressure sign, but not enough to worry about.

FIRST picture--Third case in---look fine ????????? Not to me.

It is showing some cratering, but not enough to worry about. Pick up a piece of factory loaded brass that has been shot out of a Beretta FS92, looks almost the same. Like has been said, the edges of the primers are round, there is no primer flow.

[CocoBolo]

That Grump he's telling the truth.

I have tried about every powder capable of 9 major. That said I didn't find a single one that would make major and not flatten the primer a bit.

7.8gr 3n37 with 124/grn MTG RN makes 172 pf for me. I don't use it as it is expensive, dirty, and burns hot like tight group, and the real killer is its snappy. YMMV

Apparently your gun takes a bit more powder to get there, so try a little slower one.

My load is 7.7gr of Silhouette, (reverse temp sensative so in cold weather I drop it a bit). 124gr MTG RN set 1.165, Magnum Pistol (win) or SRP.

Also good is HS6 and AutoComp.

And since you are into dirty you can try 10gr of AA#7 same bullet but increae oal to 1.180+. Shoots pretty nice.

9 major its off the charts its not for the meek and mild crowd.

Always check you brass with a magnet, some of it may not be brass.