55 gr. Bob's Boattail HPs in .25 cal at 110 FPE

[rsterne]

I have a hot .25 cal Disco that is a genuine 100+ FPE gun, so I pulled it off the wall today to try some velocity experiments with different size bullets.... I have some 50.4 gr. FN BBTs (NOE 250-51), and also some 58.3 gr. FN (NOE 250-60), plus the HP versions as well.... I tried them as cast (0.250" nose / 0.252" drive band), and they were hard to chamber in my TJ's .25 ACP barrel.... so I sized some of each down to 0.251", 0.250" and 0.249".... I tethered the gun at 2950 psi (it is modified for 3K plus) and both bullets picked up a lot of velocity between as cast and 0.251", gained more at 0.250", and then lost about 10 fps at 0.249", presumably from a small amount of blowby….

The 58.3 gr. FN were well over 900 fps, so I thought I would tune the gun for the 55.0 gr. HP version of that bullet, sized to 0.250".... Mean looking little devil....

http://i378.photobucket.com/albums/oo221/rsterne/NOE%20Bobs%20Boattails/55%20gr%20BBT%20HP_zpshvh2zs9i.jpg (http://s378.photobucket.com/user/rsterne/media/NOE%20Bobs%20Boattails/55%20gr%20BBT%20HP_zpshvh2zs9i.jpg.html)

I maxed out the preload and hit 993 fps (120 FPE), and then backed it off a turn and got 965 fps.... At that setting, off the tether, I got 2 equal shots and then a 3rd at about 940 fps, so I backed the preload out a bit more and ended up with 3 shots off tether of 956, 963 and 945 fps (111 FPE average) within a 2% ES.... Tethered, of course, it shoots 956, within a few fps.... which will give me a good platform to test these HP bullets.... The gun is loud, and not very efficient.... but at 110 FPE it should really lay a smackdown on a Marmot.... 8)

http://i378.photobucket.com/albums/oo221/rsterne/NOE%20Bobs%20Boattails/Wound%20Channel_zpsb2onv1hz.jpg (http://s378.photobucket.com/user/rsterne/media/NOE%20Bobs%20Boattails/Wound%20Channel_zpsb2onv1hz.jpg.html)

This is a penetration test of the 55 gr. BBT HP in soap at 110 FPE.... The nose came apart.... penetration of the base was 95 mm (3.75")….

Bob

[HARRYMPOPE]

what kind of groups are you getting and at what distance?

[rsterne]

Sorry, lots of snow here still.... Hope to be able to answer that question in a couple of months....

Bob

[rsterne]

I had a chance to shoot these at 100 yards today from my .25 cal Disco with the 14" twist TJ's barrel.... Here is a 3-shot group I got while sighting in the gun.... It is actually the smallest group I have ever shot with an airgun.... and rivals the best group I got decades ago with my .222 Rem handloads.... It was shot from bags, front and rear....

https://i378.photobucket.com/albums/oo221/rsterne/NOE%20Bobs%20Boattails/55%20gr%20BBT%20HP%2025%20cal%20at100%20yds_zps4vw te6au.jpg (http://s378.photobucket.com/user/rsterne/media/NOE%20Bobs%20Boattails/55%20gr%20BBT%20HP%2025%20cal%20at100%20yds_zps4vw te6au.jpg.html)

It gets lost under the dime.... These were sized to 0.250", and shot at 950 fps, like the ones in the posts above.... I shot a Ground Squirrel with one and the results were NASTY.... Here is a photo of the exit wound, the shot at 50 yards.... It hit with a THWACK and the classic "red mist"....

https://i378.photobucket.com/albums/oo221/rsterne/Game/55%20gr%2025%20cal%20HP_zpsw1ajhcr3.jpg (http://s378.photobucket.com/user/rsterne/media/Game/55%20gr%2025%20cal%20HP_zpsw1ajhcr3.jpg.html)

Bob

[35 shooter]

I’d say that will do quite nicely for a hundred yard group. Did’nt do the squirrel much good for sure.... nice shot!