AA#9 compressed charge? (pushing bullet out) [Archive] - Glock Talk

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Andrew Wiggin
11-17-2012, 03:18
I'm working up a load for 10mm 200 gr XTP. At 12.8 gr of AA#9 (Hornady's listed max is 13.2gr of AA#9), the bullets are pushing back out from 1.260" to about 1.262". Lighter charges stay put. Anybody else see this with this powder and will a compressed charge be safe, assuming everything else is okay?

steve4102
11-17-2012, 04:51
Compressing powder does not increase pressure by itself. Going above Max will, AA lists 12.5gr as Max for the 200gr XTP .

_The_Shadow
11-17-2012, 09:35
Yes it can happen, I saw this when working up loads wit Barnes all copper bullets...BTW while pressure was OK the primers were the flattest I've ever had!

Your cases need to be sized and don't use any or very little case mouth expansion to get the tightest casing grip to bullet friction...you may see better results.

However best results for velocity will be with IMR800X for the 200XTP and I find it to be less pressure than the LongShot. It is said that Underwood is using the 800X in his 10mm 200gr ammo.

Best regards!

MakeMineA10mm
11-17-2012, 10:42
I've found 12.6grs of AA#9 is my general-purpose (good in 95% of guns as far as safe pressure) max effort with the 200gr XTP. I load to 1.256", and this load goes between 1150 and 1225fps most days (depending on ambient temperature).

I'd hesitate going much higher, not because of pressure, but because when I've gone higher, I've had the same problem you are. I solved it with a roll-crimp applied while seating, all-the-while using enough pressure on the loader's handle to deform (swage) the HP closed and rounding-over the meplat and ogive a bit. I then ran the loaded rounds through a factory crimp die to take out the crimp-bulge while re-crimping again.

Those were some ugly rounds, but they fired and were safe pressure-wise. (I can't remember where I stopped, but it was at around 13.0grs.) The bottom line is that the JHPs were ruined by my mangle-job, and all that for a mere 50fps. Seriously not worth it...

Andrew Wiggin
11-17-2012, 10:48
Okay, thanks guys. I'll probably end up sticking with 12.6 gr but they're already loaded. I kinda wanted to shoot them just for the data but now that I think about it, there doesn't seem much point in collecting the data if I'm never going to use that load. Maybe I'll pull 'em.

RDub01
11-17-2012, 10:53
I'm working up a load for 10mm 200 gr XTP. At 12.8 gr of AA#9 (Hornady's listed max is 13.2gr of AA#9), the bullets are pushing back out from 1.260" to about 1.262". Lighter charges stay put. Anybody else see this with this powder and will a compressed charge be safe, assuming everything else is okay?


Yes.. If you try to compress the ball powder too much.

I ran into this with a 14.9grn charge of AA#9 with 180gr XTP's in a Starline case. Seated them to 1.26" and checking them a little later, they grew out quite a bit.
I haven't checked yet to see what charge will not do this.

I shot them long anyway, and found this load to be extremely accurate in a stock G20-SF..
(WLP primer)

ds7br
11-17-2012, 11:31
I've run up to 13.0gr with the 200XTP in Starline brass, CCI300 primers, 1.260OAL. This is in a Storm Lake barrel with a tight chamber and a heavy taper crimp (crimped to factory ammo specs). I didnt get any creep and load was compressed. I've switched to Longshot because it gives me the speed I want without compressing the load. AA#9 seems to flatten primers quite quickly for me. DONT USE THIS LOAD WITHOUT WORKING UP TO IT SLOWLY.
Dennis

Andrew Wiggin
11-17-2012, 19:41
Does Lonshot meter well?

_The_Shadow
11-17-2012, 19:45
It does meter pretty good but it needs to be tested to see from your own drop...
My RCBS Uniflow < 0.1 -/=/+

ds7br
11-17-2012, 20:41
Andrew,
As Shadow said; check it against your meter. My old Lyman throws charges to +/- 0.1 to 0.15 so I stay 0.2 below the max to account for this.
Dennis

Andrew Wiggin
11-18-2012, 13:27
I use a Uniflow too. Got it with most of my other equipment in a trade and I'm real happy I did. From everything I've heard from other folks, it seems to be the best.

WeeWilly
11-18-2012, 15:38
It does meter pretty good but it needs to be tested to see from your own drop...
My RCBS Uniflow < 0.1 -/=/+

I agree.

Same on my Dillon as your Uniflow, +/- .05grs for Longshot.

I did a test once, AA#9 and VV-3N37 meter the most accurate of all the powders I have ever used (along with BL-C(2) for rifle). My Dillon drops are right on the money round after round with #9 and 3N37.

Interestingly, in my tests I got pretty good results from Blue Dot, which was pretty amazing when you look at it physically. Out of my Dillon drop I was holding better than +/- .1gr, almost as good as Longshot.

In any case, when I am loading into the twilight zone, I always trickle.

Yondering
11-19-2012, 23:28
Okay, thanks guys. I'll probably end up sticking with 12.6 gr but they're already loaded. I kinda wanted to shoot them just for the data but now that I think about it, there doesn't seem much point in collecting the data if I'm never going to use that load. Maybe I'll pull 'em.

I may be a little late to the party, but.. I don't see any reason to pull those loads apart. With most bullets (everything I've tried) you can't jam enough AA9 into the 10mm to cause dangerous pressure, without some sort of extreme compression techniques. Max load data with this powder in many cases seems to be limited by powder capacity, not pressure. Alliant 2400 is another that does this, but without the good velocity that AA9 generates.

If your loads are only pushing the bullet back out .002", that's fine, and actually is just about right for a max compression load with this powder. You may likely find that is the most accurate load with that bullet; that's been my experience. (In my AA9 loads, consistent compression = consistent ballistic results, better than no compression or trying for 100% capacity.)

Where you'll run into trouble is adding a little more powder to that load, so the bullets set back out farther and cause hang ups in the magazine or even the chamber. Or, using that load with different brass with less case capacity. Either way, you're still not likely to encounter dangerous pressures with AA9 before running into feed/function issues.

Taterhead
11-21-2012, 22:13
I may be a little late to the party, but.. I don't see any reason to pull those loads apart. With most bullets (everything I've tried) you can't jam enough AA9 into the 10mm to cause dangerous pressure, without some sort of extreme compression techniques. Max load data with this powder in many cases seems to be limited by powder capacity, not pressure. Alliant 2400 is another that does this, but without the good velocity that AA9 generates.

If your loads are only pushing the bullet back out .002", that's fine, and actually is just about right for a max compression load with this powder. You may likely find that is the most accurate load with that bullet; that's been my experience. (In my AA9 loads, consistent compression = consistent ballistic results, better than no compression or trying for 100% capacity.)

Where you'll run into trouble is adding a little more powder to that load, so the bullets set back out farther and cause hang ups in the magazine or even the chamber. Or, using that load with different brass with less case capacity. Either way, you're still not likely to encounter dangerous pressures with AA9 before running into feed/function issues.

Great post.

I would add, that depending upon when/where A9 was made, it will have different densities so capacity will vary. 13.0 grains under a 200 XTP (WLP primer) seated to 1.26 has been around 1200 fps depending upon temps. Great groups.

Adding a mag primer can change the burn rate, so re-work if you go that route. I have seen some velocity gains with A9 and CCI 350s, but probably with some additional pressures. Speer is an example of a manufacturer that calls for mag primers in the 165 gr load, and in previously published 200 grain loads.

Andrew Wiggin
11-22-2012, 09:49
I went ahead and pulled 'em anyway and I'll just stick to 800-X for the 200 gr + bullets. Here's what I got from the rest:

AA#9 over 200 gr XTP

12.2 gr

1115
1126
1142
1116
1088


12.4

1150
1103
1121
1150
1144


12.6

1148
1170
1161
1164
1162

MakeMineA10mm
11-22-2012, 20:30
See that's why I like AA9, especially for someone new-ish to full-throttle 10mm loads. Good performance without being able to put too much in the case. Andrew - that last set of loads is extremely similar to my results. I run 12.6grs/200XTP/@1.256", and, depending on temps, I get 1125-1175fps with an ES around 10-15 fps, much like yours...

AA9 falls down with lighter bullets <180grs, and there are superior powders at that point, but I like the 10 at this load level. It was designed for this level of performance and does well.


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gator378
12-07-2012, 15:00
I'm working up a load for 10mm 200 gr XTP. At 12.8 gr of AA#9 (Hornady's listed max is 13.2gr of AA#9), the bullets are pushing back out from 1.260" to about 1.262". Lighter charges stay put. Anybody else see this with this powder and will a compressed charge be safe, assuming everything else is okay?

Same problem with 13.0 grains of AA#9. Conpressed charge never been a problem yet. I also use the 200 gr XTP.

Any Cal.
12-08-2012, 19:31
#9 gives you a nice bump in velocity when you load over length to get the extra .2 or .3g in there. Some bullets will feed at 1.270 or so, you just have to check. If nothing else, you can run a long loaded round first up in the mag. Once #9 hits its optimum pressure curve it feels much like H110 in Mag loads.

dwhite53
12-09-2012, 12:28
Just curious....

Do the rounds feed reliably after expanding out to 1.262?

Have you fired them?

If you have, do the rounds in the magazine expand further?

I wouldn't worry about it until it obviously caused a mechanical problem.

All the Best,
D. White