Wednesday, December 10, 2008

Derrick's Xisico/BAM B26-2, Part 7

Derrick finishes up with his BAM saga today, thanks again!

In the first installment on the 26-2, I mentioned that the cheek piece was a member of the mile high club. My quick and dirty fix involving a set of high mounts and an .22 dovetail-to-.22 dovetail riser didn't get the scope quite high enough. After a few sessions with a too low scope, I finally bought a Leapers .22 to Weaver adapter. Leapers part number: MNT-PMTOWL This mount coupled with a set of Leapers high profile Weaver-style rings (#RGWM-25H4) put the scope high enough for a good "heads-up" position. Scope used was--you guessed it--a Leapers. It's the 4X32 AO "Bug Buster" (SCP-432AOMDL2). The scope mount is almost 3/4 of an inch higher than normal. If I hadn't corrected for the barrel droop with such a stiff plunger spring, it's unlikely there would have been enough elevation adjustment in the scope to get on target.

Utilizing the built in recoil stop pin in the base, the mount overhangs the rear of the tube by about 1/4". The Picitinny mount comes with a 5mm x 0.80 set screw to act as a recoil stop pin when mounted on a spring piston air rifle. Past experience has proven this type of pin to be prone to failure. Once I finalize the mount location, the mount will be flush cut to the end of the rifle and a larger stop pin (or two) will be added. The rifle, like the HW's, comes with 3 recoil pin stop holes in the top of the receiver. Ideally, airgun manufacturers would redesign their spring guns to include a Picitinny/Weaver base. Use of Weaver-style rings would then eliminate the need for scope stops. Imagine, no more scope ring movement, no more broken stop pins.

The wood was very good on this gun.

I couldn't bring myself to cut down the cheek piece. I know several others have done it before with great success. I think if the gun had been shooting tight groups all along that would have happened. It's hard for me to get psyched up for an involved woodworking project when the gun doesn't shoot for beans. As it stands, I like the upright shooting position. It's just different enough to be very handy for quick off-hand shots. It comes to shoulder quickly and takes no time to find the reticule.
The bad news is that now that it shoots, it becomes really easy to justify additional time and effort. Maybe there's some stock work to be done after all.

Another shot of a lathe turned screw cup.

A few extra pics of the gun. When I was first looking into buying a BAM, there were almost no pics on the net of the gun--aside from the obligatory tiny side shot from the manufacturer. Well, there was another shot of the gun being held by a scantily clad young woman...

Looking back over the posts I wrote, I noticed I never gave the final velocity. The gun was putting out 675 fps with a light .22 cal lead pellet in stock form. With the retrofitted Weihrauch R10 mainspring and spring guide that number jumped to 748 fps. With a heavier field pellet like the Crosman Premier, the number is in the middle 720's.
Want a summation? If Xisco/BAM fixes the too short trigger adjustment spring and gets the QC on the barrel lock-up dialed, this would be a much better gun than most of what GAMO is fielding right now. If they also up the ante with a quality mainspring and a real spring guide, they will almost equal many of the German guns from just a few years ago.

1 comment:

Anonymous said...

Hi Derrick, very nice project !
I like this stock with the high comb and if only the fore end would cover the barrel block it would be great. Looking at the pics, I think the thumb hole top strap might just have sufficient meat for carving out a right hand thumb shelf for thumb-up shooters like me....
Extra wood is much better than having to add material. Good news at a time where many skimp on stock wood !

Thanks for this excellent write up.