Tight cases, can i push it more? [Archive] - Glock Talk

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JTknives
04-18-2010, 19:42
I have been doing some testing of hallow base bullets and aa#9. I mark all my cases with the powder weight and bullet type. I use a lone wolf 10mm threaded barrel in all my shooting. I fired 5 rounds of DT 155gr barnes down this barrel so I would have some test cases to compare against. The DT cases are snug/tight when put in the chamber and hard to pull out. My hotest test load was 15.25gr of aa#9 and the primers looked fine and they slip easily in the chamber. The pressure ring on the DT cases are .428 where my loads are from .426 to .4265. So can I keep going higher even though accurate says there max load is 15gr and my 15.25 looks to be under max. Thy do have a good amount of recoil which is fun. Look at my other post about rounds having pop. thanks

PCJim
04-18-2010, 21:45
JT, I don't load for 10mm and don't own one. So for that specific caliber, I can't speak.

I will state that if you are at (or above) published maximum powder charges for any caliber, you are taking a big risk if not carefully monitoring your velocities with a chronograph. I'm not an expert, and I learn just as much from these forums as others do. I do know that over pressure signs in a pistol oftentimes do not appear, especially in comparison to what we typically look for in rifle cases. You do find that there is a point in velocity where incremental increases in powder charge do not give the anticipated incremental increase in velocity, a major sign that you are well over pressure.

You really need to chronograph those rounds, as well as a few under your current charge loads, to see if you are already in that "diminished returns" area of severe overpressure.

dudel
04-19-2010, 17:54
+1 Also reducing the useful life of the brass. At some point, you're also wasting powder. Unburnt powder doesn't add to velocity.

Don

JT, I don't load for 10mm and don't own one. So for that specific caliber, I can't speak.

I will state that if you are at (or above) published maximum powder charges for any caliber, you are taking a big risk if not carefully monitoring your velocities with a chronograph. I'm not an expert, and I learn just as much from these forums as others do. I do know that over pressure signs in a pistol oftentimes do not appear, especially in comparison to what we typically look for in rifle cases. You do find that there is a point in velocity where incremental increases in powder charge do not give the anticipated incremental increase in velocity, a major sign that you are well over pressure.

You really need to chronograph those rounds, as well as a few under your current charge loads, to see if you are already in that "diminished returns" area of severe overpressure.

JTknives
04-19-2010, 22:38
+1 Also reducing the useful life of the brass. At some point, you're also wasting powder. Unburnt powder doesn't add to velocity.

Don

ya my next buy will be a chrono. not having a chrono is like building fast cars but never knowing what thy will do. any sajestions on a good one that i can take to the local indoor shooting range.

PCJim
04-20-2010, 06:28
Choice would depend upon what features you seek and how often you plan to use one. If only occasional use, get the least expensive one you can get by with, but preferably with a remote display. Personally, I use a Chrony Beta Master.

You may have problems with use in an indoor range. The "eyes" will not work if flourescent lighting is being used, unless you purchase separate IR screens (if available for your model). Also, you will probably have to set the chronograph 8-10 feet or more from your shooting position to keep from having interference from the muzzle blast.

JTknives
04-25-2010, 18:22
OK i got a Prochrono Digital. just because it was not to expensive and it stores a lot of shots and can be connected to the computer. so i tested out my what i though was hot loads.

155gr HBRN Barrys
CCI 350
AA#9 15.25gr
1. 1363
2. 1363
3. 1371
4. 1350
5. 1367

155gr HBRN Barrys
CCI 350
AA#9 13.25gr
1. 1238
2. 1242
3. 1257
4. 1277
5. 1251

155gr HBRN Barrys
CCI 350
AA#9 13.00gr
1. 1175
2. 1234
3. 1225
4. 1155
5. 1265

WiskyT
04-26-2010, 13:10
I have been doing some testing of hallow base bullets and aa#9.

155gr HBRN Barrys
CCI 350
AA#7 15.25gr



I just hope he can operate the camera on his phone with one hand.

MTPD
04-26-2010, 13:15
In my limited experience with Glock over-loads, I knew I was over the limit when the mags kept getting blown out of the grip!!!!!!!!!!!!!

JTknives
04-26-2010, 20:06
I just hope he can operate the camera on his phone with one hand.

I do not consider this a dangerous load. it right in the max zone that accurate has published. i would actually think that i am under the proclaimed pressure for a 155gr plated bullet because my bullets are hallow based therefor giving more case volume. the velocity is also right in there published ballpark.

PCJim
04-26-2010, 21:45
JT, those hollow based bullets still have to weigh the same amount as the bullets used for the published data. Given there is mass missing in the bullet base to create a hollow, the bullet would have to be longer to offset the lack of mass in the hollow base and still make the required weight.

If your hollow based bullet is a longer bullet, I would not think it will net you any additional case volume. Further, a longer bullet will likely have a greater bearing surface (bullet against barrel) thus increasing pressure.

Be careful as you experiment going forward!

dudel
04-27-2010, 16:17
JT, those hollow based bullets still have to weigh the same amount as the bullets used for the published data. Given there is mass missing in the bullet base to create a hollow, the bullet would have to be longer to offset the lack of mass in the hollow base and still make the required weight.

If your hollow based bullet is a longer bullet, I would not think it will net you any additional case volume. Further, a longer bullet will likely have a greater bearing surface (bullet against barrel) thus increasing pressure.

Be careful as you experiment going forward!

Good points. Didn't catch if the OP is using plated or lead HB projectiles. Normally, you don't want to load them hot. Too hot, and you blow a hole right through the projectile, leaving the bore ready for an interesting followup shot. The HBWC in particular has the smallest amout of projectile from the inside of the hollow base to the top of the projectile.

A typical 148gr HBWC, in 38spl, uses 3gr or less of Bullseye. A traditional target load.

Hollow base gives you some increased case volume; but the projectile is just not designed for hot loads.

WiskyT
04-27-2010, 17:01
I do not consider this a dangerous load. it right in the max zone that accurate has published. i would actually think that i am under the proclaimed pressure for a 155gr plated bullet because my bullets are hallow based therefor giving more case volume. the velocity is also right in there published ballpark.

What's dangerous is the way you transpose AA7 and AA9. You might want to figure out which powder you are actually using as you journey onward with your "research".

DEADLYACCURATE
04-27-2010, 17:28
Is it aa7 or aa9

DEADLYACCURATE
04-27-2010, 17:29
What's dangerous is the way you transpose AA7 and AA9. You might want to figure out which powder you are actually using as you journey onward with your "research".

beat me to it

JTknives
04-27-2010, 22:15
What's dangerous is the way you transpose AA7 and AA9. You might want to figure out which powder you are actually using as you journey onward with your "research".

Thanks guys for catching that typo. i had just gotten done posting some #7 data and must have not though about it.