Shot the scope off of my Beeman R7

[rcmodel]

Been using it daily for squirrel control the last few weeks.
And put 20 rounds through it yesterday re-checking zero.

Nothing abnormal.

So, this evening I whacked two more squirrels at about 20 yards.

Then noticed the scope had slipped back until the rear ring was clear off the receiver!!!

Remounted it this evening with blue lock tight in the clamp grooves.

But, it Looks like I better start shopping for a scope stop clamp!!

BTW: This it the perfect example of why high-power rifle scopes don't hold up on air rifles.
Firearm recoil try's to kick out from under the scope, and it wants to slide forward.

The effect of air rifle recoil is the exact other direction, and leaves the scope sliding rearward as the rifle recoils forward at piston impact.
rc

 

[cslinger]

You just need rings with a scope stop screw.

It is amazing how much recoil a spring gun imparts in all directions.

 

[rcmodel]

The R7 has two scope stop pin holes in the top of the receiver.
And one of them is in the right place for the rings I'm using.

But the rings don't have a pin hole.

So I guess my next step is to drill the rear ring for the matching stop pin.

rc

 

[Chevota]

If they don't have a stop pin then I wonder if they're airgun rings? Some rings like cheapies for 22LR (or cheap airgun) are so weak that even with a stop they still won't work. Another problem with cheap rings is they rely so much on the pin that the pin may cut into or damage the hole in the receiver, or break/bend and plow a groove in it, and with such a nice gun that would be a shame.
These are what I like, they look good, are cheap and work:
http://tinyurl.com/oe7rxna
http://tinyurl.com/ousf2zk
Optionally you can add two more clamp screws to the one-piece mount, which also looks nicer imo. And/or replace the set screw with a 6mm which if needed will be less likely to damage the gun.

 

[rcmodel]

I like the looks of that 1-piece mount you linked.

Could you possibly measure it front to back and between the rings for me??

Thanks
rc

 

[Chevota]

...

 

[rcmodel]

Thank you!

rc

 

[rcmodel]

1 piece base on order!!

rc

 

[RecoilRob]

Are you by chance using a lightweight pellet? Or could the piston seal be getting a bit worn? Or the barrel/chamber seal leaking a bit? If everything is sealed up properly and the pellet weight matching the size of the powerplant...it really shouldn't be slamming terribly hard at the front of the chamber. Ideally the piston should just stop short of bouncing if everything is tuned correctly and will feel very smooth shooting.

Of course it's a good idea to use the 1 piece base to hold things securely, but will the gun pass the 'tissue test'? (piece of tissue layed on barrel/chamber joint...it shouldn't move during firing) Just a wee bit of leakage will prevent the pressure from stopping the piston and it'll slam. And if that's good, a heavier pellet will take more pressure to start down the barrel which should cushion it a bit better as well as smack the tree rats a little harder.

 

[rcmodel]

I don't think so.
Gun is just well broken in, far from needing new seals.

No air seal leakage with a piece of paper napkin laid over the barrel joint seal.

I'm using 7.9 grain Crossman Premimum HP pellets the gun seems to shoot best.

No clashing / crashing sound or vibration when you fire it.
Very quite & smooth in fact.

I think these are just cheap .22 rings I had in the junk, of unknown Pedregree.

They are only 3/4" wide, so two screws holding two 3/4" clamps just isn't enough surface area.

I'm confident the new mount with four clamp bolts, a 4" long clamp, and recoil lug pin will be the final answer.

rc.

 

[RecoilRob]

The tissue test really tells the story if the barrel seal is good or not. Those old R7's are a really sweet shooting gun for sure. Have you ever tried the 10.5 Crosman Premier? My Chinese copy of the R7 (BAM B25) just loves them to death...but also shoots the 7.9's out of the big brown box well too. The heavier pellets just feel smoother to me and I believe they are moving fast enough to work OK on things they hit.

I've never tried shooting it with a scope not secured in pinned rings though a Dana 48 proved to be quite a challenge to keep the scope from moving back. The solution there ended up being a Maccarri spring to tame down the power a bit as it proved that the 48 powerplant is actually too big for .177's and even the heaviest pellets would piston slam something fierce. Now it cocks easy and shoots smooth with the 10.5's about 890 or so.

 

[rcmodel]

I haven't tried heavier pellets.

I bought the R7 LNIB from a guy, and got about half a gazillion pellets with it.

It shot the Preimum HP so well, I didn't do any further testing.

But, I really think the only problem is the cheap .22 tip-off rings I used.

rc

 

[rcmodel]

Chevota
Wanted to thank you for recommending that 1-piece scope mount!!

I have put about 100 rounds through it so far, and it ain't going nowhere!!

Finally cooled off enough this evening to finish sighting it in at longer range.

2 sighter shots to see where it was shooting, 5 clicks right, 1 down, and then shot a 3-shot group at 30 yards.

Good enough for tree rat control i'm thinking!!



rc