WST sanity check [Archive] - Glock Talk

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njl
10-14-2010, 19:10
I've spent a few days scouring the net collecting WST 9mm data and loaded a few test rounds. Here's what I've done:

130gr BBI "coated lead" 1.140" OAL
4, 4.2, and 4.4gr

147gr GDHP 1.115" OAL
3.4 and 3.6gr

I'm not going to blow up my G17, am I?

tjpet
10-14-2010, 20:07
Nope.

My favorite 147grn./WST load is 3.8grns. Good for 950fps, give or take, and superb accuracy with low recoil.

fredj338
10-14-2010, 23:48
You should be fine, I have gone to 3.6gr w/ 147grLTC & 4.8gr w/ 124grLTC w/ varying OAL. I gave up on WST w/ the heavier lead bullets though, just couldn''t get the accuracy I do w/ WSF or Unique.

njl
10-15-2010, 06:33
Sounds good. Hopefully I'll have some chrony numbers this weekend.

bballer182
10-15-2010, 07:18
You should be fine, I have gone t. 3.6gr w/ 147grLTC & 4.8gr w/ 124grLTC w/ varying OAL. I gave up on WST w/ the heavier lead bullets thougg, just couldn;t get the accuracy I do w/ WSF or Unique.


Damn fred were drinking grandpas cough medicine while you typed that post?

fredj338
10-15-2010, 09:51
Damn fred were drinking grandpas cough medicine while you typed that post?
Sum thimes eye geet en a hory & the key bord duz what it wants.:rofl: See, it can get a lot worse, but then that would be abrasive.:yawn:

Bob2223
10-15-2010, 10:14
Sum thimes eye geet en a hory & the key bord duz what it wants.:rofl: See, it can get a lot worse, but then that would be abrasive.:yawn:


:rofl:

Your just a rude, crude and mean person Fred !












Bob :supergrin:

GioaJack
10-15-2010, 10:18
:rofl:

Your just a rude, crude and mean person Fred !












Bob :supergrin:


Post count whore!

(I've been watching too many news reports about Jerry Brown.)


Jack

Bob2223
10-15-2010, 10:35
Post count whore!

(I've been watching too many news reports about Jerry Brown.)


Jack

Ain't you suppose to be working on a press or something ? :upeyes:

I guess some presses take a weeks training and a manual that looks like the health care bill to set up. :whistling:



Bob

fredj338
10-15-2010, 13:35
:rofl:

Your just a rude, crude and mean person Fred !


Bob :supergrin:
I'll blame it on my enviroment. It's amazing anyone from Kalif can be functional w/o govt help.:rofl:

njl
10-17-2010, 17:38
I made it back with all my fingers. I even forgot to take my leather work gloves with me (just in case).

130gr BBI "coated lead" 1.140" OAL
4gr WST 994.0-1054fps 1021avg 60.08ES 20.19SD
4.2gr WST 1004-1053fps 1031avg 49.51ES 15.45D
4.4gr WST 1000-1053fps 1033avg 52.43ES 16.06SD

So...what's it mean when you put in more powder and don't get any increase in velocity?

147gr GDHP 1.115" OAL
3.4gr WST 838.5-883.7fps 860.8avg 45.12ES 15.09SD
3.58gr WST 857.0-918.3fps 889.3avg 61.31ES 20.51SD

My best group though was with this load

147gr GDHP 1.115" OAL
3.28gr Universal 814.2-852.8fps 837.1avg 38.61ES 11.83SD

I fired 10 shots of each. With this last one, I had a really small group, 5 of the shots of which made one hole not much bigger than a nickel at 10yds. If not for the cost of the gold dots, this would probably be a great load for GSSF.

PCJim
10-17-2010, 18:00
So...what's it mean when you put in more powder and don't get any increase in velocity?

It usually indicates you have reached or exceeded the maximum charge level for that particular recipe and specific firearm.

njl
10-17-2010, 18:27
It usually indicates you have reached or exceeded the maximum charge level for that particular recipe and specific firearm.

That's what I thought...but what's the explanation for what's going on that the velocity stops increasing? There's obviously got to be more pressure...but for some reason, it's not pushing the bullet any faster.

TonyT
10-17-2010, 18:35
I have never seen any W-W pressure tested data for the 9mm using WST.

PCJim
10-17-2010, 18:36
I don't know the science/physics behind what is happening. My theory is that the bullet can move only so fast due to friction. While additional pressure will move the bullet somewhat faster, the pressure:incremental velocity ratio has deteriorated to the point that the required pressure to gain additional velocity begins to exceed the design for the caliber.

Kind of like trying to get more water flow thru a 1/2" garden hose. You can put 200 psi on the hose and the flow will not increase. You will, however, rupture the hose.

FLSlim
10-17-2010, 18:47
PC, I'm not sure I understand the physics either, but you sure offer a great analogy. Sounds good to me.

njl
10-17-2010, 21:26
I forgot to mention...the best part about today's chrony work was all the free brass. The part of the range I typically use is divided by gravel filled wood walls into half a dozen separate pistol ranges. When I arrive, I always claim a range (park there) and then walk through the rest scanning for brass if they're not in use. I found a pretty good amount on arrival...mostly 9mm, a few .45acp, .45lc, .38, .380, and even 2 10mm. Then I found the range I'd actually parked at had a bunch of 9mm left behind.

I did my shooting, picked up my brass and the left behind brass, and then walked the ranges again...and while doing that found another large quantity of 9mm and .380. I probably shot about 150 rounds and came home with what must be about 500 9mm cases and maybe 100 .380s. I don't even have/reload for a .380.

shotgunred
10-18-2010, 04:58
380 is hard to come by and makes good trading stock.

k8ysv
10-18-2010, 06:24
As for no increase with more powder. I'm not a very experienced reloader yet, but it would seem to me that this would have to do with the burn rate of the powder. If the rate of burn is sufficiently slow, it's likely that not all of the powder is burned by the time the bullet leaves the barrel. Therefore, adding MORE powder will do nothing to increase velocity. You'll just end up with a bigger fireball as the extra powder flashes out of the open barrel.

But that's just my guess. I could be wrong.

njl
10-18-2010, 06:34
WST is a kind of fast one...so I don't think that's what's happening. I think it's more like PCJim suggested. i.e.

Each smokeless powder converts to gas in a certain amount of time. Peak pressure will depend on how quickly that powder to gas conversion happens. At some point, the bullet starts to move, and the volume increases, allowing pressure to fall or making room for more gas if the powder to gas conversion is still in progress. If the burn rate is fast enough, pressure gets higher than is useful (bullet can probably accelerate only so fast, and once that rate is reached, all you're doing is adding pressure).

I'm certainly no expert in reading brass for pressure signs...but I have seen other people shooting 9mm major and their flattened primers. None of mine looked any different from usual, and I did actually mark the brass differently for each load so I could easily tell the fired casings from each other...so I'm going to guess that I didn't have crazy high pressure.

fredj338
10-18-2010, 12:54
WST is a kind of fast one...so I don't think that's what's happening. I think it's more like PCJim suggested. i.e.

Each smokeless powder converts to gas in a certain amount of time. Peak pressure will depend on how quickly that powder to gas conversion happens. At some point, the bullet starts to move, and the volume increases, allowing pressure to fall or making room for more gas if the powder to gas conversion is still in progress. If the burn rate is fast enough, pressure gets higher than is useful (bullet can probably accelerate only so fast, and once that rate is reached, all you're doing is adding pressure).

I'm certainly no expert in reading brass for pressure signs...but I have seen other people shooting 9mm major and their flattened primers. None of mine looked any different from usual, and I did actually mark the brass differently for each load so I could easily tell the fired casings from each other...so I'm going to guess that I didn't have crazy high pressure.
Jim is on the right track. I am not sure of the exact physics of it but it's not just the powder burn rate but the relationship of the gas expansion to the bore diameter. I have seen exactly that in the 9mm w/ WST, especially w/ heavier 147gr bullets. You ad powder & the vel stays flat. I haven't seen this in the 45acp w/ any bullet wt. The vel steadily increases as you add powder & I have stopped before reaching pressure signs, so while it could happen in the 45acp as well, I am betting it's more to do with the smaller bore size.
My rule of thumb, when I stop getting vel increases, it tells me I have reached the rpessure level for that cartridge/bullet/powder combo, regardless of any add'l. pressure signs. I have seen it in rifle rounds too, certain powders, bullets & bore size.