147 gr 9mm Atlanta Arms Ammo vs. my reloads

[Quag]

In a G17 I shoot 147gr MG, 3.6 grns 231 1.13 OAL mixed brass Win SP magnum primers chrono at 914 fps ave, 22 SD, range 872-941. I was practicing with a new light DPM recoil spring and got a couple of failure to retracts.

I had some Atlanta Arms (AA&A) 147 remanufactured ammo with me I use in matches, so I tried that. The last time I chrono AA&A it was 869 to 890 fps, I think their web site says 890.

What really surprised me was the increased energy with the AA&A ammo (my accuracy did not suffer). It was much louder than my reloaded ammo and no failure to retracts.

Any ideas on the causes of this? The velocities are pretty close. My thought is AA&A is using a hotter powder than Win 231 like Tite Group.

thanks

[Butterpuc]

Was it the same box of ammo from AA&A that you chrono-ed at the 869fps? AA&A may be having similar issues as the rest of us finding powder and they may have switched.

I would have thought the opposite of what you thought.... If it has more perceived recoil and was louder, I would expect that to be a slower burning powder. With Titegroup burning really fast all the burning takes place in the barrel and is complete before the bullet exits. When I use Titegroup and N-320 with 147gr I get a much quieter report than others using 231/HP-38. Not necessarily less recoil but the report is quieter.

As far as dual recoil springs... I am currently using a gen4 Glock 34. I do notice the slide just barely ejects the case when I run loads under 130PF.

Btw, with my N-320 and 147gr loaded at 1.135" I get 6SD, so my load is quite consistent. When working up loads I use the typical 5-10 loaded rounds to find something I may like, then load 20-30 rounds to get a larger sample size for measuring SD. You mentioned your load is 22SD, it could be with that high spread you may have fired a low power factor round and the slide didn't recoil correctly.

[Quag]

Was it the same box of ammo from AA&A that you chrono-ed at the 869fps? AA&A may be having similar issues as the rest of us finding powder and they may have switched.

I would have thought the opposite of what you thought.... If it has more perceived recoil and was louder, I would expect that to be a slower burning powder. With Titegroup burning really fast all the burning takes place in the barrel and is complete before the bullet exits. When I use Titegroup and N-320 with 147gr I get a much quieter report than others using 231/HP-38. Not necessarily less recoil but the report is quieter.

As far as dual recoil springs... I am currently using a gen4 Glock 34. I do notice the slide just barely ejects the case when I run loads under 130PF.

Btw, with my N-320 and 147gr loaded at 1.135" I get 6SD, so my load is quite consistent. When working up loads I use the typical 5-10 loaded rounds to find something I may like, then load 20-30 rounds to get a larger sample size for measuring SD. You mentioned your load is 22SD, it could be with that high spread you may have fired a low power factor round and the slide didn't recoil correctly.

Good thoughts. My chrono on AA&A ammo was only 6 rounds and was bought last spring. The AA&A I shot yesterday was a new batch. Typically I have not noticed much difference between my reloads and AA&A. But then I have not shot it inside like yesterday. How many grains of N-320 do you use? My shots with the 22SD was 10 (minium sample size). I think to do a proper comaprison I'll have to chrono 15 to 20 of each.

Also when I was firing my reloads with the same formula 147grns MG and 3.6 grns 231 and I had the stock trigger and springs I had no LS or failures to eject. I understood when I put in this trigger group and lighter recoil springs it would take some fiddling. You may be onto something there about loads<130PF.

[Butterpuc]

Was it the same box of ammo from AA&A that you chrono-ed at the 869fps? AA&A may be having similar issues as the rest of us finding powder and they may have switched.

I would have thought the opposite of what you thought.... If it has more perceived recoil and was louder, I would expect that to be a slower burning powder. With Titegroup burning really fast all the burning takes place in the barrel and is complete before the bullet exits. When I use Titegroup and N-320 with 147gr I get a much quieter report than others using 231/HP-38. Not necessarily less recoil but the report is quieter.

As far as dual recoil springs... I am currently using a gen4 Glock 34. I do notice the slide just barely ejects the case when I run loads under 130PF.

Btw, with my N-320 and 147gr loaded at 1.135" I get 6SD, so my load is quite consistent. When working up loads I use the typical 5-10 loaded rounds to find something I may like, then load 20-30 rounds to get a larger sample size for measuring SD. You mentioned your load is 22SD, it could be with that high spread you may have fired a low power factor round and the slide didn't recoil correctly.

Good thoughts. My chrono on AA&A ammo was only 6 rounds and was bought last spring. The AA&A I shot yesterday was a new batch. Typically I have not noticed much difference between my reloads and AA&A. But then I have not shot it inside like yesterday. How many grains of N-320 do you use? My shots with the 22SD was 10 (minium sample size). I think to do a proper comaprison I'll have to chrono 15 to 20 of each.

Also when I was firing my reloads with the same formula 147grns MG and 3.6 grns 231 and I had the stock trigger and springs I had no LS or failures to eject. I understood when I put in this trigger group and lighter recoil springs it would take some fiddling. You may be onto something there about loads<130PF.

147gr FMJ and HP, 3.2gr Titegroup

147gr coated/moly lead, 3.2gr N-320

[superdude]

It could simply be a different gunpowder than your reloads. A different gunpowder can produce much more/less recoil for the same velocity.

http://38super.net/Pages/Gunpowder%20and%20Recoil.html

[HOGRIDER]

In a G17 I shoot 147gr MG, 3.6 grns 231 1.13 OAL mixed brass Win SP magnum primers chrono at 914 fps ave, 22 SD, range 872-941. I was practicing with a new light DPM recoil spring and got a couple of failure to retracts.

I had some Atlanta Arms (AA&A) 147 remanufactured ammo with me I use in matches, so I tried that. The last time I chrono AA&A it was 869 to 890 fps, I think their web site says 890.

What really surprised me was the increased energy with the AA&A ammo (my accuracy did not suffer). It was much louder than my reloaded ammo and no failure to retracts.

Any ideas on the causes of this? The velocities are pretty close. My thought is AA&A is using a hotter powder than Win 231 like Tite Group.

thanks

From AA&A News publication:

http://www.atlantaarmsandammo.com/NEWS/SSUSA1209_AArms_.pdf

All of our powder is either St. Marks or Vihtavuori.

[Quag]

Thx Danny is good people treats me like a pro (which I'm not)

[Sandbagger123]

i have a freind that uses 147gr AA ammo exclusively. looking at his gun from the soot that is left on the front after shooting, it reminds me of what i get when i used to reload with Bullseye powder.

[Justsomeguy]

Most commercial reloaders will use powders that are "blended" and not available as canister powders to the general public. In fact, a lot of those commercial powders which Alliant sells ARE variants of Bullseye that are treated for retardation, flake size and other things and will be identified with "BE" and a number or other letters. Heck, rumor has it that Power Pistol is one such variant which became a canister powder.

[Quag]

It could simply be a different gunpowder than your reloads. A different gunpowder can produce much more/less recoil for the same velocity.

http://38super.net/Pages/Gunpowder%20and%20Recoil.html

thats a good web site, I booked marked it

[Quag]

One of the things I notice about AA&A is their crimp is slightly tighter than mine. It runs .377 to .378. I have my crimp set at .379 to .380. They state their Blue Box ammo chronos at about 890 fps, my chrono of thier loads confirms this. They calculates to a PF of 130. I have heard that if you set a PF<130 you may get failure of slides to retract, I don't know if thats just hearsay or its real. Maybe a tighter crimp gives slighly higher pressures for minor PF loads. I just know with my AA&A ammo I never seem to have a misfire, my reloads not so much but I'm working on it (getting an extended striker for my Glock).

[Justsomeguy]

Atlanta Arms has for many years been pretty savvy to the gun gamer's needs and built suitable ammo. The power factor your gun may shoot with stock springs is a question only you can answer, but in my experience, a lot of stock guns need a bit more than even 130PF to run reliably, especially the short guns with less than 4" barrels, and even some of the longer ones. Most will require something more like 140PF ammo to run the gun, but yours might not. Grip and arm tension of the individual shooter may allow the cases to dribble out at even 130PF.

Crimp is usually relative to feeding more than increasing pressure or "holding the bullet". Case tension is most responsible for those factors.

[Quag]

Good point on the power factor, I use a lighter recoil spring in both of my competition pistols in which I shoot a low PF ammo. I find if I drop below 130 PF (9mm) funny things start happening. I just increased my powder by .2 grains and I am getting more consistent slide racks and feeds.

If crimp does not affect the pressure, what is case tension a function of? Obviously the amount of powder and how "hot" the powder is but what else, depth of the bullet seating?

Thx

[BlueOvalBandit]

If crimp does not affect the pressure, what is case tension a function of?

For a taper crimp

Sizing mainly, belling/expanding and crimping all contribute to decreasing neck tension.

A roll crimp is a mechanical lock so the above doesn't really apply.

[Justsomeguy]

Case tension is related to sizing die diameter. It is the tension the case puts on the bullet when seated, or resistance to movement of the bullet caused by the "grip" of the case on the bullet.

[FLHX]

I have been using the 147gr 9mm ammo since I got back into shooting and it runs in all my 9's from Glock's to 1911's. I just got some of the 40 minor for my G35 and it ran great in it. This is my first 40 and I didn't find it all that snappy as I have heard in the past about 40.