project QB760P custom pumper

[matthew_H]

hey guys have not been around here in a while and it nice to visit again . i had the idea to build this when after a couple years my qb78 started to leak . i took it apart to reseal it and never got around to it . i had bought a new 760 with plans of getting a rifled barrel and a wood stock set . and  i ended up with a msp qb78 . it has a slighty moded cr760 valve stock pump cup . the back end is all qb78 , hammer and ajustable trigger .







its not done yet, still need to refinish the main tube and build a pump handle but it is fully functional and accurate .  i need to come up with a way to build a rear sight as it has the archer carbine barrel and has no sights , for now i have a old Bushnell 4x on it but would really like to come up with some iron sights . the front sight should not be a problem but the rear sight is .i also need to build a barrel band of some kind .for now it has a powermaster 66 barrel support with a shim under it .







i could use some input on what to call this rifle , i have been calling it QB760P . please let me know of any tips for this build or comments or questions .







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[SDale]

WOW!!! Lookin good! Nice Hybrid you've got goin there!

Keep it up! More pics when she's done!!!

[Jaymo]

All it needs is a left handed bolt and the wood 760 forend.  Now I'm thinking about buying a couple more 1377s and a 760 and a 2100 just for Frankensteining together. I like the way you think. Originally I was going to build a PCP out of my B5-10 but I'm leaning toward another direction.

[Jaymo]

BTW, I see you liked my suggestion for adding the P to the end of it to designate Pumper. I'm telling ya, put a wood 760 forend on it and it'll look like an old Benji. I'm seriously thinking about hybridizing my QB78 with my B5-10.
Hmm, I wonder if a 760 or 2100 tube is longer than a 1377 tube? I need to build a long tube/long barreled 1377 hybrid carbine/pistol. Kind of a pumper version of a DQ outlaw.

The great thing about your Frankenstein(don't take that as an insult, it's not) is that it's not affected by the cold Michigan winters the way CO2 is.
That and it's a short/light/handy carbine with a lot of potential.

[matthew_H]

i want to get a wood forearm i forgot that crosman made a 760 with a wood stock . i need to look into ordering that part . yeah not being affected by weather is why pumpers are my fav kind of air rifle , plus they are not hold sensitive and tend to be accurate and least my 2100 is and so far this is too . i wish i had a chrony to test power , i thinks its around 550- 600 but thats what this gun ran on with co2 because of the short barrel .

yeah i liked your suggestion thank you . i think the 760 and 1377 tubes are the same pump stroke . but i know ,at least mine old power master 66 tube is much longer and with a decent flat top  (not a home done one like mine lol ) could make some real power mine is not that bad but it needs a new barrel .

[howie1a]

Hi Mendoza has a iron sight both in peep or blade sight that fits on 3/8 " scope groves pyrmid has them maybe that will work for a rear sight for you howie

[Jaymo]

I'm seriously considering installing a rifled 760 barrel and a 2100 tube onto my 1377. One of the things I like so much about these Crosman air guns is that I can Frankenstein them together.
A Benjamin 392 tube looks to be the perfect diameter to Frankenstein onto a QB78.
I really like the hardwood, corncob forend on the wood stocked 760. That's one reason I suggested it. The other reasons are that it should be CHEAP to buy from Crosman, it's a perfect fit to your 760 pump lever, and the resemblence it will bear to the old Benjamins.  I, for one, salute your ingenuity in making the QB760P hybrid.
Now, if I Frankenstein a Benji 392 pump/tube together with a QB79 breech/valve, I should be able to make a powerful .25/.30/.35 caliber MSP that has great parts availability.
I'm thinking I'd like to adapt a B50 tube/valve to a QB78 and maybe even a 1377. That should make for some serious power potential.
I'm glad you brought this kind of "outside the box" thinking with you. I was hoping you wouldn't confine it to ONLY the Crosman forum, which I also like.

[matthew_H]

thanks , its been realy fun and quite satisfying to build this . its the pumper i always wish some company so i just built it myself .i just tore down my 66 power master and swapped my diy flat top and valve into my QB760P .its much louder , and its a older all brass valve and it dumps 20+ pumps with no leftover air . i need to get out and shoot it , but we are in the middle of a blizzard .....

[matthew_H]

its nearly done , i just need to get a new forearm .

[matthew_H]

specs are

ported and polished 760 flat topped valve

custom non adjustable flattop piston

archer carbine qb78 barrel

deluxe stock

bushnell 4x18 Japanese .22 scope (parallax adjusted for air gun ranges)

valve is pined in with two setscrews

poly tube transfer port seal

dumps 25 pumps no problem and is dead nuts accurate

[dave2288]

VERY NICE!!!!  how does she shoot?

[Jaymo]

I like it.