BLUF: Is it safe to use an insert that 'converts' a larger-bore-lower-pressure cartridge to a smaller-bore-high(er)-pressure cartridge?
Details:
I was looking over the available Shotgun Inserts, esp here: http://www.mcace.com/shotguninserts.htm as i have bought from Mr. Dube in the past and been pleased (*). They are solid steel and fit well in the chanber/barrel of the host platform. i like them and the idea of them ALOT and want to expand my use of them...SAFELY!
Now I am wondering if a couple specific conversions are safe in guns of good working order:
- 410bore-to-218 Bee or 22 Hornet: the 410shotgun pressure is comparitively low at ~13000 psi. Whereas the 218 Bee and 22 Hornet are 40-45000 psi.
and,
- 20ga-to-30-30WIn:
with the 20ga at ~12000psi and the 30-30 at 32000psi.
or, similarly,
- 12-ga-to-45-70Govt at ~11500 and 28000psi, respectively.(**)
The larger caliber above conversions have a lesser difference (absolute and percentage-wise) in pressures between the 2 chamberings, but also have more massive projectiles and powder charges.
Given the surface area differences in the breechplate of the break-open shotgun design versus the new, smaller surface area cartridge rim, and the smaller cartridge higher chamber pressure but now contained in a sleeve of solid steel (the insert); what are my safety concerns?
Anyone have real expertise in the area?
anyone use one of these inserts without problem?
with problems?
thanks!
C-
(*) out of ignorance perhaps, i have always used conversions that stay in the 'low-pressure' range: example: a 12ga-to-22LR. Even though 22LR is approx DOUBLE the pressure of a 12ga; iit is so small that the hunk of steel insert looked ample to contain it. I have also tried 12-ga to 38SPL and used the target wadcutter loads; but have not yet dared to try 357 Magnum in the insert.
(**) for that matter and if it helps, the MCACE insert for 12ga can also be made in 444Marlin which has pressure at 44000psi and similar dimensions to the 45-70, so it may give some indication to the strength of the steel.
Details:
I was looking over the available Shotgun Inserts, esp here: http://www.mcace.com/shotguninserts.htm as i have bought from Mr. Dube in the past and been pleased (*). They are solid steel and fit well in the chanber/barrel of the host platform. i like them and the idea of them ALOT and want to expand my use of them...SAFELY!
Now I am wondering if a couple specific conversions are safe in guns of good working order:
- 410bore-to-218 Bee or 22 Hornet: the 410shotgun pressure is comparitively low at ~13000 psi. Whereas the 218 Bee and 22 Hornet are 40-45000 psi.
and,
- 20ga-to-30-30WIn:
with the 20ga at ~12000psi and the 30-30 at 32000psi.
or, similarly,
- 12-ga-to-45-70Govt at ~11500 and 28000psi, respectively.(**)
The larger caliber above conversions have a lesser difference (absolute and percentage-wise) in pressures between the 2 chamberings, but also have more massive projectiles and powder charges.
Given the surface area differences in the breechplate of the break-open shotgun design versus the new, smaller surface area cartridge rim, and the smaller cartridge higher chamber pressure but now contained in a sleeve of solid steel (the insert); what are my safety concerns?
Anyone have real expertise in the area?
anyone use one of these inserts without problem?
with problems?
thanks!
C-
(*) out of ignorance perhaps, i have always used conversions that stay in the 'low-pressure' range: example: a 12ga-to-22LR. Even though 22LR is approx DOUBLE the pressure of a 12ga; iit is so small that the hunk of steel insert looked ample to contain it. I have also tried 12-ga to 38SPL and used the target wadcutter loads; but have not yet dared to try 357 Magnum in the insert.
(**) for that matter and if it helps, the MCACE insert for 12ga can also be made in 444Marlin which has pressure at 44000psi and similar dimensions to the 45-70, so it may give some indication to the strength of the steel.