1377 is done, chrony test 739 fps, only 10 pumps Video Updated 2/17

Crosshairs · January 07, 2011, 01:56:56 PM

Thanks i got all the brass from gmac custom parts. the trigger is real nice.i did polish the trigger at friction points.HaHa i did pump to 12 got up to 746 fps not sure how many pumps it will take.
Mike

NorthStaR · January 07, 2011, 02:08:50 PM

Nice, top banana! If you look in the Chrony LCD reflection I can see you pumping it up for the shots!

Congrats!

Crosshairs · January 08, 2011, 02:10:10 PM

lol my daughter said the same thing.

Crosshairs · January 12, 2011, 05:13:01 AM

I did pump it 15 times and got 798 fps i wonder how many it will take !
Mike

Ddevil54r · January 12, 2011, 05:58:15 AM

Ugh, you're depressing me lol... I want mine to hit 700 and I'd be happy. I don't see a need to go my higher than 1000 fps with any airgun to be honest. 700 for a pistol(let alone nearly 800!) is absolutely astounding! Isn't the super sonic 1200 fps? That would kill accuracy for such a light projectile. If you have an accurate pistol reliably shooting in the 7's you have a winner in my book!

quickster47 † · January 12, 2011, 02:24:35 PM

The only good thing, in my book, about getting higher velocity (FPS) out of an airgun is that it then allows you to use heavier pellets which increases muzzle energy and that gives you higher knockdown power for them thar pesky varmints at longer ranges.

Carl

Crosshairs · January 12, 2011, 04:22:18 PM

I also think higher FPS is better for a long shot, will shoot str8 a longer distance.

ray1377 · February 16, 2011, 06:50:41 PM

not to sound like a broken record.
but could you possibly give us a break down of each part you installed and what brand part you used.
And any other tuning you might have done to attain these numbers.
I'd love to get that from mine.
Thanks
Ray

Crosshairs · February 16, 2011, 07:20:50 PM

Ray not a problem, the barrel is from a 1760,all the brass and adjustable trigger is from GMAC custom,the flat top piston and valve is from Mellon Air,the stock is from crosman.the wood is from RB grips, oh the breech is from crosman. I think one reason i got such good numbers is the 1377 i used is from the 80s and well broke in.Any help you need just ask.Here is a pic with the scope and wood installed.Gun complete.
Mike

ray1377 · February 16, 2011, 07:28:19 PM

I must be doing something wrong then.
I have a mellonair FTP kit in mine along with a 1760 barrel.
I've also modified the valve by trimming down the valve stem dia. and taking the corner out of the exhaust port and polished the inside. Also changed out the valve spring to a lighter weight one so I could get it to dump 30+ pumps at one shot.
I've also did the poly transfer tube mod.
I must have a leaking o-ring or something.
I don't get anywhere near what your getting.
But I wished I could.
I'm gonna tear my gun down again and inspect those seals and rings.
Thanks
Ray

Crosshairs · February 17, 2011, 01:41:50 AM

Ray when you changed your piston and valve did you deber the inside of the tube ? and yes check your transfer port seal.
Mike

ray1377 · February 17, 2011, 04:27:19 AM

Well I tried to.
I thought I did.
But there must be a reason why I can't get that kind of fps.
Ray

quickster47 † · February 17, 2011, 04:51:28 AM

Ray, what kind of numbers are you getting? And I must admit Mike's numbers do seem high. Of course he could be using a non lead pellet like maybe a 6 or 7 grain that would give those kind of numbers. What pellets are you using?

Carl

ray1377 · February 17, 2011, 05:47:03 AM

With a 24 inch barrel, 7.9grain CPHP's and like 30 pumps only yielded me a best of 712fps.
And he's getting more than that on only 10 pumps!!!!
Man I'm jealous.
I always wanted to try and break 800fps. if at all possible.
Right now I have converted the same 1377 to a 1322 with a 14inch .22 barrel.
And with 30 pumps and 14.3 grain CPHP's it only shoots them at a best of 525fps.
Oh well, somethings wrong somewhere.
Back to the drawing board.
Thanks
Ray

quickster47 † · February 17, 2011, 02:24:22 PM

Personally, I think when some one publishes FPS numbers they should include the pellet weight so we can get a better gauge of what the gun is really putting out.

I have a AS2250XT with a .177 24" barrel running on CO2 that I can get 1106 fps with using Prometheus ThUnder BOLT pellets weighing in at 5 grains. That ain't much fpe but the fps numbers are impressive.

Carl