I've joined the Pumper club ...

tayloriand · July 05, 2011, 08:01:38 PM

Greeting chaps,
Well I couldn't hold out any longer.
CAPOC is full of pumpers and I've got myself a 1377
http://i249.photobucket.com/albums/gg227/andyrobbo_2008/Picture0002.jpg
It's early days at the moment but it came with black grips and pumper forearm and the trigger and internals are all stock.

Does anyone have any number using a Mellon FT piston and valve at 10 pumps. Is 10fpe realistic with a 12" .22. Are the Brass/Ali pistons vastly superior to Delrin? Let me know what your pumper is doing and what have you done to it.

Cheers
Ian

Crosshairs · July 05, 2011, 10:17:40 PM

I have a 1377 with Mellon piston and valve with a 24" barrel and get 804 fps out of it Charlie does good work

Mike

quickster47 † · July 05, 2011, 10:56:13 PM

Well CONGRATULATIONS and it is about time. Now you are beginning a whole new adventure. Good luck and trust me, you will love that gun in no short order.

Carl

1377x · July 05, 2011, 11:02:53 PM

congrats and welcome to the club!

myself i like ac's pistons and valve work
havent tried mellons valve but did have his piston and broke it my fault improper adjustment

NorthStaR · July 05, 2011, 11:47:12 PM

Has anyone tried the GMAC ones?

http://www.gmaccustomparts.com/epages/BT3197.sf/en_GB/?ObjectPath=/Shops/BT3197/Products/1377FTKIT

Was interested to know as I thought I may indulge...

slothart · July 06, 2011, 12:24:30 AM

i have a Mellon FT Piston & Valve with a 12 inch barrel, but mine is .177. That said:
With 10.5g CPH I was getting 7.7fpe/578fps at 12 pumps. (I didn't write down numbers for a 10 pump shot when I was testing that time)

That was with a bad seal at the transfer port. I've since fixed the leak, but have only chronied it with 7.56g pellet (618fps at 10 pumps and 649fps at 12 pumps with the 7.56g. It was an 11fps improvement compared to the numbers recorded with the bad seal).

1377x · July 06, 2011, 03:22:19 AM

good number's no trying to see who's bigger
my ac valve and ac delrin piston produced 650fps 10 pumps 7.9 cp
with the mellon piston and ac valve velocity dropped to 638fps
if you look at ac's piston has the o-ring slighly closer to edge of the piston than mellon's.iirc that little difference makes bigger gains according to the headspace thing.not a technician just an assembler,not to good with tech names

slothart · July 06, 2011, 04:14:20 AM

Wow... same length barrel?

I'm actually trying to place an order with AC Customs for a 1377 wire stock, but have yet to hear back from him. I think it has been a week since I emailed him. If I hear back from him, I might have to add one of his brass pistons to the order.

1377x · July 06, 2011, 04:26:59 AM

Quote from: slothart on July 06, 2011, 04:14:20 AM
Wow... same length barrel?

I'm actually trying to place an order with AC Customs for a 1377 wire stock, but have yet to hear back from him. I think it has been a week since I emailed him. If I hear back from him, I might have to add one of his brass pistons to the order.

stock 10" barrel 650fps 7.9 cp 10 pumps forgot to mention some of this last time

ayerstg · July 06, 2011, 04:58:46 AM

QuoteDoes anyone have any number using a Mellon FT piston and valve at 10 pumps. Is 10fpe realistic with a 12" .22

IRRC, Medic is getting over that with a Mellon piston and valve at 10 pumps but using a 24" barrel. 12 or 13 is the most air the stock hammer spring could dump in his; he had to add a spring to dump all the air beyond that. Disco hammer spring next, I guess.

He's on 24 hr shift so I can't verify ATM, but that's what I recall. Suspect you could get that muzzle energy with a 14 - 16 inch barrel but maybe not quite at 10 pumps. I'll ask him to refresh my memory when I see him sometime tomorrow evening.

NorthStaR · July 06, 2011, 10:53:37 AM

I guess it's a NO on the GMAC valve as far as members experience with them.

If 1377X is getting more out an AC delrin setup then I think I'll try GMAC's. His looks to be made of Delrin?

Postage is cheaper too - same country!

tinker · July 06, 2011, 11:14:42 AM

The 1377 I have now is using the Mellon FT piston & valve. But it isn't stock, modded valve, reduced volume, lighter spring etc. It sports 18" Mellon barrel and 6 1/2" TKO shroud and shoots an avg 696 fps using the Crosman Destroyer EX .177 pellets at 10 pumps.
Yes i'll get some pictures up in another post when I get the pictures taken

tayloriand · July 06, 2011, 01:49:19 PM

Thanks for the replies chaps.
Anyone else using the GMAC valve and FT piston.
From your feedback 10 fpe/10 pumps/12" and .22 may be optimistic

Cheers
Ian

NorthStaR · July 06, 2011, 01:55:44 PM

It would appear not. BUT I plan to get one real soon. I have a 20"barrel in .22 on a what was a 1377 now 1322 sniper pumper!

It'll be interesting to see how it improves the general output.

Crosshairs · July 06, 2011, 03:03:05 PM

Quote from: 1377x on July 05, 2011, 11:02:53 PM
congrats and welcome to the club!
myself i like ac's pistons and valve work
havent tried mellons valve but did have his piston and broke it my fault improper adjustment

I also have used AC Piston and Valve and they work great and the piston is adjustable, just as good numbers.So now you need to get another 1377 and get a mellon and a AC seup

Mike
The 1377 here has the AC piston and valve i can get just over 700 fps with 10 pumps it has a 14 1/2" barrel.