Much more-so than butchering a $20 Crosman!
However, since my .22 Brocock Sniper XR has been relegated to single use for some time now (35 Foot Pound class in Bench-Rest Silhouette matches), I decided to convert it into a 30 foot pound pistol. Actually, a rifle/pistol convertible.
Chopping the Lothar Walther barrel to 15" took a considerably more stressful leap of faith than chopping cheap and available Crosman barrels. Recrowning the polygonally-rifled muzzle was a bit trickier, as well. However initial accuracy testing of the little carbine suggests no accuracy was lost in the barrel butchery.
And velocity testing proves my hope of retaining at least 28 foot pounds of the 23" rifle barrel's 38.4 foot pounds was a conservative estimate. At full power (level 4 on the power knob), Mongo Mag is getting 865 FPS/30.1 foot-pounds with 18.13 JSBs. On power level 3 it gets 831 FPS/27.8 FP, level 2 = 736/21.8, and level 1 = 578/13.5. With no baffling in the shroud yet, it's LOUD. Hearing protection required! However I intend to reattach the moderator fitting to the end of the shroud, probably as the final step in the conversion.
Meanwhile I've ordered hardware to fabricate couplers to allow quick detach/reattach of the buttstock to the pistol grip, once I make those cuts. That part being unchartered territory, I'm hoping a combination of much forethought, excellent hardware, and very careful fabrication will do justice to the final rig.
The idea is to still use it in carbine form for 35 FP class Bench-Rest Silhouette competition, in pistol form for Extreme Pistol Field Target competition at power level 2 (after I reduce regulator pressure to drop power level 2 below 20 FP), and create a new Extreme Pistol Field Target class with a 30 foot pound power limit.
I'm thinking the new class will also be called Mongo Mag; and could be included in regular Extreme Pistol FT, or stretch EPFT maximum target distances to around 75-80 yards. Meanwhile I might use Mongo Mag in Extreme Rifle FT matches (for funzies). Regardless, Mongo Mag will no longer be single purpose.
Anyone else interested in 75-100 yard Extreme Pistol Field Target competitions?
However, since my .22 Brocock Sniper XR has been relegated to single use for some time now (35 Foot Pound class in Bench-Rest Silhouette matches), I decided to convert it into a 30 foot pound pistol. Actually, a rifle/pistol convertible.
Chopping the Lothar Walther barrel to 15" took a considerably more stressful leap of faith than chopping cheap and available Crosman barrels. Recrowning the polygonally-rifled muzzle was a bit trickier, as well. However initial accuracy testing of the little carbine suggests no accuracy was lost in the barrel butchery.
And velocity testing proves my hope of retaining at least 28 foot pounds of the 23" rifle barrel's 38.4 foot pounds was a conservative estimate. At full power (level 4 on the power knob), Mongo Mag is getting 865 FPS/30.1 foot-pounds with 18.13 JSBs. On power level 3 it gets 831 FPS/27.8 FP, level 2 = 736/21.8, and level 1 = 578/13.5. With no baffling in the shroud yet, it's LOUD. Hearing protection required! However I intend to reattach the moderator fitting to the end of the shroud, probably as the final step in the conversion.
Meanwhile I've ordered hardware to fabricate couplers to allow quick detach/reattach of the buttstock to the pistol grip, once I make those cuts. That part being unchartered territory, I'm hoping a combination of much forethought, excellent hardware, and very careful fabrication will do justice to the final rig.
The idea is to still use it in carbine form for 35 FP class Bench-Rest Silhouette competition, in pistol form for Extreme Pistol Field Target competition at power level 2 (after I reduce regulator pressure to drop power level 2 below 20 FP), and create a new Extreme Pistol Field Target class with a 30 foot pound power limit.
I'm thinking the new class will also be called Mongo Mag; and could be included in regular Extreme Pistol FT, or stretch EPFT maximum target distances to around 75-80 yards. Meanwhile I might use Mongo Mag in Extreme Rifle FT matches (for funzies). Regardless, Mongo Mag will no longer be single purpose.
Anyone else interested in 75-100 yard Extreme Pistol Field Target competitions?
Must thou keep circumsising thou Brococks? I hope a trophy and check comes with that operation brother. I’m actually surpised you aren’t partnered with some company designing quality competition air pistols by now.
