cheby Posted April 8, 2022 Share Posted April 8, 2022 I heard that WST powder is somewhat temperature sensitive. Does anyone have any data supporting that? I am about to start using this powder for my 40SW major loads and wonder how much I will need to adjust in July Link to comment Share on other sites More sharing options...
eisenhow Posted April 10, 2022 Share Posted April 10, 2022 WST is reverse temperature sensitive: higher temp = lower velocity. One of my squad mates went minor at A7 with his limited gun that had already been bumped to open. Link to comment Share on other sites More sharing options...
AHI Posted April 10, 2022 Share Posted April 10, 2022 WST and clean shot are reverse temperature sensitive. Link to comment Share on other sites More sharing options...
OpenshooterMclass4lyfe Posted April 10, 2022 Share Posted April 10, 2022 1 hour ago, eisenhow said: WST is reverse temperature sensitive: higher temp = lower velocity. One of my squad mates went minor at A7 with his limited gun that had already been bumped to open. Slightly off topic. How did your friend get bumped to open? Link to comment Share on other sites More sharing options...
kitestir Posted April 10, 2022 Share Posted April 10, 2022 9 hours ago, OpenshooterAclass4lyfe said: Slightly off topic. How did your friend get bumped to open? I am going to take a shot ()in the dark and say his mags didn’t fit the gauge…… Link to comment Share on other sites More sharing options...
Out of Ammo Posted April 11, 2022 Share Posted April 11, 2022 I've been shooting WST for years and it's definitely reverse temperature. I've been told about shooters who would put their bullets into a cooler before chrono. Link to comment Share on other sites More sharing options...
cheby Posted April 11, 2022 Author Share Posted April 11, 2022 So let’s say my ammo is 950 f/s at 50degree. How much would it slow down at 90? Link to comment Share on other sites More sharing options...
caspian guy Posted April 11, 2022 Share Posted April 11, 2022 7 hours ago, cheby said: So let’s say my ammo is 950 f/s at 50degree. How much would it slow down at 90? Take 10 rounds of ammo put them out in the sun on a warm day, take 10 rounds, put them in a ziplock bag in your cooler with an ice pack, take 10 rounds and keep them at ambiant temp. Shoot them over your chrono back to back. Link to comment Share on other sites More sharing options...
zzt Posted April 14, 2022 Share Posted April 14, 2022 WST is not actually reverse temp sensitive. It is hottest at mid temps and slows down when it is cold or really hot. If your major is 172PF at 65-70 deg., you are safe a freezing and 95. I can't find the curve right now, but the slopes are mild. Same with minor at 132. Link to comment Share on other sites More sharing options...
CHA-LEE Posted April 14, 2022 Share Posted April 14, 2022 26 minutes ago, zzt said: WST is not actually reverse temp sensitive. It is hottest at mid temps and slows down when it is cold or really hot. If your major is 172PF at 65-70 deg., you are safe a freezing and 95. I can't find the curve right now, but the slopes are mild. Same with minor at 132. I want to see the data on this. I also want to know how you achieved different AMMO temperatures while comparing velocities in "Hot, Cold, Medium" temps. I shot WST for years in 40 Major and during my AMMO tempreture testing WST was significantly faster at close to Freezing temps and significantly slower at Hot temps at or above 100 Degrees. Most people think that the powder/temp testing is associated with the ambient temperature which you are shooting in. The ambient temp has much less effect on the burn rate of the powder versus the temperature of the actual Ammo. The ammo temp is usually similar to the ambient temp because the ammo is usually exposed to the current ambient temp conditions. But if you artificially heat or cool ammo loaded with WST powder you will absolutely see a velocity difference that is inverse of the ammo temp. Hotter temp ammo = Slower velocity. Colder temp ammo = Faster velocity. When I was shooting WST I would artificially heat the ammo to 110+ degrees then immediately chrono it to verify that it still made major PF velocity. You can artificially heat the ammo by simply letting it sit in the direct sun light, or just lay it over the heating vent in your vehicle. For what its worth, my testing showed that 110+ degree Temp WST 40 cal Ammo making 165 - 166 PF was also 175 - 180 PF at Freezing temps. This all being shot out of a 5 inch KKM Barrels. If you are going to use WST make sure it still makes power factor when its 110+ degrees. Link to comment Share on other sites More sharing options...
cheby Posted April 14, 2022 Author Share Posted April 14, 2022 4 minutes ago, CHA-LEE said: I want to see the data on this. I also want to know how you achieved different AMMO temperatures while comparing velocities in "Hot, Cold, Medium" temps. I shot WST for years in 40 Major and during my AMMO tempreture testing WST was significantly faster at close to Freezing temps and significantly slower at Hot temps at or above 100 Degrees. Most people think that the powder/temp testing is associated with the ambient temperature which you are shooting in. The ambient temp has much less effect on the burn rate of the powder versus the temperature of the actual Ammo. The ammo temp is usually similar to the ambient temp because the ammo is usually exposed to the current ambient temp conditions. But if you artificially heat or cool ammo loaded with WST powder you will absolutely see a velocity difference that is inverse of the ammo temp. Hotter temp ammo = Slower velocity. Colder temp ammo = Faster velocity. When I was shooting WST I would artificially heat the ammo to 110+ degrees then immediately chrono it to verify that it still made major PF velocity. You can artificially heat the ammo by simply letting it sit in the direct sun light, or just lay it over the heating vent in your vehicle. For what its worth, my testing showed that 110+ degree Temp WST 40 cal Ammo making 165 - 166 PF was also 175 - 180 PF at Freezing temps. This all being shot out of a 5 inch KKM Barrels. If you are going to use WST make sure it still makes power factor when its 110+ degrees. Thanks Charlie. That’s exactly what I was looking for Link to comment Share on other sites More sharing options...
zzt Posted April 15, 2022 Share Posted April 15, 2022 19 minutes ago, CHA-LEE said: I shot WST for years in 40 Major and during my AMMO tempreture testing WST was significantly faster at close to Freezing temps and significantly slower at Hot temps at or above 100 Degrees. And it would have been faster yet if you chrono'd at 65. I don't artificially heat or cool ammo. I just chrono ambient temp. I leave it out, let it col or heat to whatever ambient is, then chrono. And why on earth are you shooting in 110 deg. weather? That's insane. You must be out West where there is zero humidity. Oh, I see you are from CO. Have no idea how WST varies from sea level to a mile high. I can say that at sea level +, what I presented was accurate with the 45 ACP bullseye loads I tested. Link to comment Share on other sites More sharing options...
CHA-LEE Posted April 15, 2022 Share Posted April 15, 2022 14 hours ago, zzt said: And it would have been faster yet if you chrono'd at 65. I don't artificially heat or cool ammo. I just chrono ambient temp. I leave it out, let it col or heat to whatever ambient is, then chrono. And why on earth are you shooting in 110 deg. weather? That's insane. You must be out West where there is zero humidity. Oh, I see you are from CO. Have no idea how WST varies from sea level to a mile high. I can say that at sea level +, what I presented was accurate with the 45 ACP bullseye loads I tested. Do you measure the actual temperature of the ammo itself? or just assume that it achieves the same temp as ambient by leaving it out? Doing temperature testing without actually measuring the temperature of the ammo isn't very useful. Digital IR Style Temp gauges are fairly cheap these days. Get one and test this stuff with actual REAL data to leverage. I also want to point out that, yes I have tested the velocity of WST ammo at varied "Middle" temps between 32 - 110 degrees and the velocity change tracked pretty consistently with the temp change. Lastly, yes there are matches hosted in temps north of 110 degrees. More importantly, there are major matches with chrono stages were the staff leaves the ammo sitting in the sun so the ammo is HOT when you chrono it vs the ambient temp. Link to comment Share on other sites More sharing options...
caspian guy Posted April 15, 2022 Share Posted April 15, 2022 36 minutes ago, CHA-LEE said: Do you measure the actual temperature of the ammo itself? or just assume that it achieves the same temp as ambient by leaving it out? Doing temperature testing without actually measuring the temperature of the ammo isn't very useful. Digital IR Style Temp gauges are fairly cheap these days. Get one and test this stuff with actual REAL data to leverage. I also want to point out that, yes I have tested the velocity of WST ammo at varied "Middle" temps between 32 - 110 degrees and the velocity change tracked pretty consistently with the temp change. Lastly, yes there are matches hosted in temps north of 110 degrees. More importantly, there are major matches with chrono stages were the staff leaves the ammo sitting in the sun so the ammo is HOT when you chrono it vs the ambient temp. 100 percent the last thing... Noticing that is what started me chronoing my ammo after heating and cooling it. Link to comment Share on other sites More sharing options...
eisenhow Posted April 15, 2022 Share Posted April 15, 2022 On 4/10/2022 at 9:14 AM, OpenshooterAclass4lyfe said: Slightly off topic. How did your friend get bumped to open? This was probably 10 years ago. Back then they still had the 500 gun rule in limited. He had an SVI sight tracker that hadn't met the 500 mark yet and ran into Amadon at the safe table. He got bumped to open and our next stage was chrono where he went minor. Link to comment Share on other sites More sharing options...
AHI Posted April 16, 2022 Share Posted April 16, 2022 It is fairly easy to test cold to hot temperature effects.50 rounds in the freezer overnight .(-40 deg). 50 rounds in the refrigerator overnight (40 ish deg). 50 rounds on a heating pad overnight (100/110 deg).50 rounds at room temperature(?) I chrono at home so no problem keeping at temps. If you have to travel you will need a few empty coolers to maintain the temperatures.(smaller the better). Haven't tested WST . But several others. Clean shot was the worst. Over 200fps from extreme cold to hot. Link to comment Share on other sites More sharing options...
mikeone Posted June 17, 2022 Share Posted June 17, 2022 (edited) . Edited June 17, 2022 by mikeone Link to comment Share on other sites More sharing options...
LeonCarr Posted June 18, 2022 Share Posted June 18, 2022 (edited) Some numbers from February and this morning. 230 Grain Precision Delta FMJ, 4.8 WST, Winchester Brass, Winchester LPP, 1.255 OAL .470 taper crimp, fired from stock barrel Glock 21 Gen 4. Chronograph numbers from February 6, 2022, temperature 30 degrees, 810,789,798,788,801 average 797.2. Chronograph numbers from June 18, 2022, temperature 86 degrees, 760,768,767,761,760 average 763.2. IME/IMO it is reverse temperature sensitive. Load is near maximum, please follow all safe reloading practices. Just my .02, LeonCarr Edited June 18, 2022 by LeonCarr Link to comment Share on other sites More sharing options...
Farmer Posted June 18, 2022 Share Posted June 18, 2022 3 hours ago, LeonCarr said: Some numbers from February and this morning. 230 Grain Precision Delta FMJ, 4.8 WST, Winchester Brass, Winchester LPP, 1.255 OAL .470 taper crimp, fired from stock barrel Glock 21 Gen 4. Chronograph numbers from February 6, 2022, temperature 30 degrees, 810,789,798,788,801 average 797.2. Chronograph numbers from June 18, 2022, temperature 86 degrees, 760,768,767,761,760 average 763.2. IME/IMO it is reverse temperature sensitive. Load is near maximum, please follow all safe reloading practices. Just my .02, LeonCarr Slower at higher temps but also more consistent. ES-8 VS ES-22 Link to comment Share on other sites More sharing options...
LeonCarr Posted June 19, 2022 Share Posted June 19, 2022 Yeah, I shot those 5 over the chrono this morning and my first thought was "Yeah, that'll work." Link to comment Share on other sites More sharing options...
cheby Posted June 19, 2022 Author Share Posted June 19, 2022 8 hours ago, LeonCarr said: Some numbers from February and this morning. 230 Grain Precision Delta FMJ, 4.8 WST, Winchester Brass, Winchester LPP, 1.255 OAL .470 taper crimp, fired from stock barrel Glock 21 Gen 4. Chronograph numbers from February 6, 2022, temperature 30 degrees, 810,789,798,788,801 average 797.2. Chronograph numbers from June 18, 2022, temperature 86 degrees, 760,768,767,761,760 average 763.2. IME/IMO it is reverse temperature sensitive. Load is near maximum, please follow all safe reloading practices. Just my .02, LeonCarr So it is over 4%. A load at 170PF during winter would not make a major PF with this temperature range Link to comment Share on other sites More sharing options...
cnote Posted February 25, 2023 Share Posted February 25, 2023 I just loaded up my 40 major loads after a few years of shooting open. I was surprised to see them at about 177 PF, on a 32* F day. Came here to "remember" if it was reverse temp sensitive. and now its coming back to me. I load them to make PF in the warm weather, when I would do most of my shooting ...... Thank you for being here guys! Link to comment Share on other sites More sharing options...
cnote Posted February 25, 2023 Share Posted February 25, 2023 On 4/10/2022 at 9:26 PM, cheby said: So let’s say my ammo is 950 f/s at 50degree. How much would it slow down at 90? I just loaded 200 grain 40's, got 888 fps / 177 PF at 32* F. Same gun, same load would get me about a 170/172 at a summertime major match a few years back. Link to comment Share on other sites More sharing options...
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