GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: CarsonRatSniper on January 03, 2014, 01:27:53 AM
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Gun:
Regulated 2540 Carbine with 16" TJ's 25 ACP 1:14" twist barrel
Pellet:
25.4 grain JSB lubed with Napiers Power Pellet Lube - picked straight from the tin
Velocity:
735 fps - 30 ft lbs
Sight:
Sig Sauer Micro Red Dot reflex sight - 4 MOA dot
Distance:
50 yards
5 shot group without 1/2-20 LDC
(http://i94.photobucket.com/albums/l83/mhossack/Snapbucket/th_84988B15-orig.jpg)
String:
734.1
730.1
735.4
734.3
729.3
The 3 consistent shots are all touching and well under 1/2".
The 2 fliers were given away by the velocity variation.
With LDC attached
(http://i94.photobucket.com/albums/l83/mhossack/Snapbucket/th_1C8EFB62-orig.jpg)
String:
731.9
729.6
727.7
731.7
731.5
Even with an extremely light amount of clipping (which I have fixed) the group looks the same except for hitting low and left.
3 shots almost touching and 2 fliers.
If I were to sort pellets by glass roll test I promise you it would be one hole groups.
And don't forget - this is at 50 yards using a non magnified red dot sight!!!
I highly recommend a TJ 25 ACP barrel liner if you are planning a custom build.
They shoot cast very well and JSB's exceptionally well.
My 25 Challenger has a 27" TJ's 25 ACP barrel and it also shoots one ragged hole at 50 yards pushing the 25.4 grain JSB's @ 1020 fps.
If anyone was wondering...........there is your answer.
YES!!! They're VERY accurate!
:)
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Please share some pictures of what makes up such a conversion / parts list
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(http://i94.photobucket.com/albums/l83/mhossack/Snapbucket/th_1065541B-orig.jpg)
(http://i94.photobucket.com/albums/l83/mhossack/Snapbucket/th_DABD2AB1-orig.jpg)
Challenger power adjuster, Disco spring, Prod striker, Prod grip frame, BOSS Max Flow valve modified (.250" throat, 3/16" exhaust drilled @ 17* & 90* then hand ported to match throat), Delrin poppet, 3/16" I.D. steel transfer port, Disco fill nipple, stainless steel extended probe bolt, 3000 psi 13 ci (213cc) JDS bottle with 1800 psi regulator, crosman steel breech, TJ 25 ACP 16" barrel, custom dropped shorty Crosman stock, 2250 fore arm, single point sling attachment @ butt and topped with a Sig red dot.
;D
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Mike, I agree that the TJ's liner is a great barrel in .250 cal.... but to think that your less than 1% velocity spread (~6 fps ES) is going to cause fliers at only 50 yards is dreaming.... That spread would basically be unnoticable at twice that distance....
Bob
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You're right - something was different though. This gun ALWAYS has an ES of 1.3 - 1.7, so maybe the skirts were out of round or something.
The LDC had some light clipping. The end cap was at .322" so I opened it up to .341"
I will make it back out next Tuesday and shoot some batched pellets and re-post.
Its an excuse to shoot more and chase the one hole group!
:)