Custom long-stroke MSP target gun

[JMJ in NC]

I posted this over on the Crosman forum (and CAPOF too), but here are the details. I wanted to build a multi-pump 10M target gun that I could shoot that could be shortened so that my kids could use it too. My hope is that one of them might become interested in airguns as well and I'd have a shooting partner.

The gun was made from parts I had already, purchased, or made. The goal was minimal cash outlay, maximize adjustability, and hit 500 fps with 4 pumps or less.

Barrel - Lothar Walther .177, 19"
Breech - Crosman Steel
Compression tube - Crosman Powermaster 66, modified to accept Crosman breech & trigger frame
Trigger/frame: Crosman 1701P
Sights - Daisy/Avanti

The current setup has an adjustable flat-top piston & ported valve. There is a volume reducer in the valve.
I have a hammer preload adjuster built into the upper rear stock. LOP adjusts from 10" to 15". The compression tube is about 3/4" longer than a 1377, so it builds pressure rapidly.

I think the steel breech, sights, and the trigger frame are only parts that I did not modify or make. Trigger components are polished, of course.

Performance - with RWS Basics, shooting 465 fps at 3 pumps, 527 fps at 4 pumps. So, pretty close to my target.

Here it was almost complete:


And assembled:


Compared to my Avanti 753:


Compared to my Crosman 1377 carbine:


I still need to tweak it some, but it shoulders and handles well, and accuracy of the barrel is what you'd expect from LW.

JMJ

[Hobbyman2007]

Nice build, I don't have a multi pumper yet. This gives me some ideas .

[robertr]

Very nice , great job on the build. I would love to have that.

[Rob M]

awesome build, what are the numbers after 5 pumps?

[JMJ in NC]

awesome build, what are the numbers after 5 pumps?

Rob,

This was designed as a 10M gun, 500 fps target velocity with 7 grain wadcutters. The valve will retain air after 4 pumps, so velocity will not increase much at 5 pumps in the current setup.

Here is the current configuration, BTW.



This gun is slated to get a slightly longer 2100 compression tube and linkage, which should get me to 500fps at 3 pumps.

JMJ

[ray1377]

Thats really sweet looking.
Love the stock with all the adjustments!
Ray

[Rob M]

makes perfect sense, and the more swept volume the better , awesome project

[Motorhead]

Very well done ... a very unique rig you have built yourself.

[bhh]

Very nice! 

Where did you get the LW barrel? Thanks.

[YEMX]

I remember seeing this- still a beauty!!!

[JMJ in NC]

Where did you get the LW barrel?.

Precision Airguns was clearing out some LW barrels (last year IIRC). I got this one for $40 shipped.

Here's another view


JMJ

[bhh]

Thanks. That was a great price.

[Tater]

Nice looking build John.