GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Big Bore AirGun Gate => Topic started by: bduares on May 12, 2021, 06:22:11 PM
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I have swaged 5 different weights of the same SWC slug, same batch of lead, to test over the chrony with the AEA .357 Challenger. Here are the best results from the 5 weights, all shot at 24 MPa or within 20 psi of 3500.
M/S FPS FPE
105.4 gr Lead 284 932 203
106.4 gr Powder Coat 285 935 204
115.2 gr Lead 285 935 223
117.4 gr Lead 268 879 201
124.8 gr Lead 262 859 204
145.6 gr Lead 225 738 176
At least with my rifle weight of projectile increase results in an fpe increase curve up to 115 gr then it starts falling again. My Challenger appears to have an issue with "long slugs" that do not fit the magazine. I can load them into the barrel, but it is a real chore to try to close the bolt once they are loaded, where I literally have to hit the bolt hard with my hand to get it to close and lock all the way. There is no such issue with the slugs that fit into the magazine.
I did have an apparent result of 225 fpe with a 103.8 gr slug of the same type going 988 fps when I first got the rifle, but that was with a different chrony. It may or may not be reliable and to date that was the single best fpe I have seen with it. 223 fpe is the best I have seen with the new chrony.
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After making a few more slugs I found that 112.6 gr slugs 11.75 mm long fit nicely in the magazine. 12 mm might be the max length that allows the plastic magazine cover to rotate.
The 150 gr mold casts slugs I can't use as-is due to their length but they are easily cut down to any length I want to put through the swage press. I need to make an adjustable slug cutter as right now I am cutting them freehand by eye with a non-ratcheting PVC pipe cutter a bit like a cigar cutter on steroids. The same cutter has been easily modified by some people to make it into an adjustable swage core/bullet cutter so I may try that next.
https://youtu.be/roszzM5UatY
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It sounds like you would need to open up the barrel lead to accept the longer slugs, with easier loading results, many have done this when maxing out the ammo weight.