Hey all quick question regarding gas checks. On hard cast bullets at what average velocity would a 405gr .458 bullet benefit from a gas check? I assume softer bullets are more effected by the hot gases. Is there actually a real world difference? This is for a 4570 modern rifle with 23 3/4" barrels. I plan to reload to top trap door or slightly higher depending on accuracy so I will push 1600-1700fps hopefully
gas checks and velocity
- Thread starter brybenn
- Start date
sisiphunter
Regular
- Location
- Saskatoon, SK
Gc's are strange little things. The main thing to look at ispressure not really velocity. In my 8mm mauser ive gotten up above 2100fps with a plain base boolit. The general rule is over 1200-1400fps a gc is needed. Now we know that isnt always the case. Fit is the biggest thing to know. You want. 001" over groove diameter.
As for hardness. I tried hard boolits and such. I usually het some.leading.if size isnt right. My favorite alloy is 50/50 ww/range scrap or pure. Also just good ole ww air cooled is good.
For a great place to learn more about cast boolits and a ton of experience with 45-70 check out castboolits website forum.
Hope this helps. Matt
As for hardness. I tried hard boolits and such. I usually het some.leading.if size isnt right. My favorite alloy is 50/50 ww/range scrap or pure. Also just good ole ww air cooled is good.
For a great place to learn more about cast boolits and a ton of experience with 45-70 check out castboolits website forum.
Hope this helps. Matt
at the pressures the OP mentioned(trap door) he is probably ok without using any gas checks as long as a he has a good fitted bullet.
if your cast bullets are designed for gas check and have the step in the base i would Recommend using a gas check.
since that unfilled gap between the bullet and the bore at the base will promote gas cutting if not filled with the gas check.
if your cast bullets are designed for gas check and have the step in the base i would Recommend using a gas check.
since that unfilled gap between the bullet and the bore at the base will promote gas cutting if not filled with the gas check.
Don't worry about getting some lead in your 45 calibre bore. It likely won't lead up, but if some occurs, it is easy to remove. Also, velocity as a barrel leading factor is over rated. If the barrel is going to lead, it will collect lead at 800 fps.
Meat at the super market stores used to come in blue packages. This material was very resistant to heat and worked almost as good, maybe even better, than coppper gas checks. I cut discs from them and loaded them behind the bullet in 44 magnum for revolvers. They seemed to actually keep lead from forming in the barrel.
Meat at the super market stores used to come in blue packages. This material was very resistant to heat and worked almost as good, maybe even better, than coppper gas checks. I cut discs from them and loaded them behind the bullet in 44 magnum for revolvers. They seemed to actually keep lead from forming in the barrel.
roberto mervici
Regular
- Location
- Prov.Quebec, Canada
Hello,
I have a 45/70 build using a siamese mauser action and a commercial 458 barrel, I reload using NOE 350 gr. gas check mold and wheel w. water dropped, average speep at 15 ft. 2230 fps. after 40 rounds very little leading.
Also I did use cast 405 plain base at 1550 fps, no problem.
Accuracy with the 350 grain gas check, worst results 1.5" for 5 shoots at 50 yrds
I have a 45/70 build using a siamese mauser action and a commercial 458 barrel, I reload using NOE 350 gr. gas check mold and wheel w. water dropped, average speep at 15 ft. 2230 fps. after 40 rounds very little leading.
Also I did use cast 405 plain base at 1550 fps, no problem.
Accuracy with the 350 grain gas check, worst results 1.5" for 5 shoots at 50 yrds
It really seems to depend more on the pressure than it does actual velocity.
Using PB 405 gr cast from ww at .001" over barrel size, I don't get leading using IMR4895 but I do using IMR4198. Same velocity - 1650 fps in both. Figure that out.
My theory is that the faster burning IMR4198 has a higher peak pressure that starts to break down the base of the bullet and leave lead in the barrel. IMR 4895 is a slower powder that can produce equal velocity at a lower pressure. In this case the velocity is not the only factor causing leading, or both powders would produce the same results.
Using PB 405 gr cast from ww at .001" over barrel size, I don't get leading using IMR4895 but I do using IMR4198. Same velocity - 1650 fps in both. Figure that out.
My theory is that the faster burning IMR4198 has a higher peak pressure that starts to break down the base of the bullet and leave lead in the barrel. IMR 4895 is a slower powder that can produce equal velocity at a lower pressure. In this case the velocity is not the only factor causing leading, or both powders would produce the same results.
