With or W/out gas checks - The Firearms Forum

army mp · 04-28-2009, 02:35 PM

I read an article a few months back in hand loader magazine, They suggested that gas checked bullets could significantly increases pressure. I tested 15 each, checked and unchecked, Lyman 358156 bullets cast out of wheel weights and lyno-type mix, heat treated to a BHN of 28. All components new Win, brass Win, primers the powder load Mid, range in all 30 rounds I shot them out of a 357 Dan Wesson. 6 inch barrel. I Cleaned the barrel between checked and unchecked rounds. Chronographs of rounds fired average was 1014.5 FPS. With the checked bullets traveling. An average of 15 FPS faster. Has anyone else tested this, with a different bullet , Hardness of bullet or caliber, and what results did you get. I’m suspicious of the hardness of the unchecked Bullets. As to with the BHN of 28 did the unchecked bullets seal properly..

Texxut · 04-28-2009, 08:12 PM

All else being equal, I doubt it significantly increases pressure. The real advantage of the gas check is, it allows you to push the bullet faster without leading.

Popgunner · 04-28-2009, 09:57 PM

Gas checks do increase pressure some. Volocity is a poor indicator of pressure. Velocity is a product of pressure over time. You can spike pressures that don't stay higher & don't show much if at all on a chrono. A test was done by one load manual with a known 270 win load. The flash hole was drilled out one drill size larger & pressure spiked 28,000psi higher but velocity only increased by 40 fps. "Complete Guide to Handloading" if I remember.

Best to go back to starting load when changing-in gaschecks to a load.

04-28-2009, 02:35 PM	#1
army mp V.I.P. Member Join Date: Jan 2009 Location: western Pa, Posts: 479	With or W/out gas checks I read an article a few months back in hand loader magazine, They suggested that gas checked bullets could significantly increases pressure. I tested 15 each, checked and unchecked, Lyman 358156 bullets cast out of wheel weights and lyno-type mix, heat treated to a BHN of 28. All components new Win, brass Win, primers the powder load Mid, range in all 30 rounds I shot them out of a 357 Dan Wesson. 6 inch barrel. I Cleaned the barrel between checked and unchecked rounds. Chronographs of rounds fired average was 1014.5 FPS. With the checked bullets traveling. An average of 15 FPS faster. Has anyone else tested this, with a different bullet , Hardness of bullet or caliber, and what results did you get. I’m suspicious of the hardness of the unchecked Bullets. As to with the BHN of 28 did the unchecked bullets seal properly.. -->

04-28-2009, 08:12 PM	#2
Texxut V.I.P. Member Join Date: Feb 2009 Location: Utah Posts: 267	Re: With or W/out gas checks All else being equal, I doubt it significantly increases pressure. The real advantage of the gas check is, it allows you to push the bullet faster without leading.

04-28-2009, 09:57 PM	#3
Popgunner Advanced Senior Member Join Date: Dec 2005 Contributor Posts: 1,764	Re: With or W/out gas checks Gas checks do increase pressure some. Volocity is a poor indicator of pressure. Velocity is a product of pressure over time. You can spike pressures that don't stay higher & don't show much if at all on a chrono. A test was done by one load manual with a known 270 win load. The flash hole was drilled out one drill size larger & pressure spiked 28,000psi higher but velocity only increased by 40 fps. "Complete Guide to Handloading" if I remember. Best to go back to starting load when changing-in gaschecks to a load.