Those of you with BKL's and riser blocks....

[Jetmugg]

I'm about to put a set of BKL riser blocks and BKL "high" rings on my 1712. This should be the same setup that I've seen others on this site use. The Miami Hurricanes rifle and the GB Packers rifle appear to be using this setup.

I currently use Burris Sig Zee's with the offset inserts.

My question is for the other folks using BKL's and high-dollar scopes (my scope isn't too high dollar, but I still don't want to kink the tube).

Are you folks shimming the back ring and then lapping for the scope tube, or are you shimming/not lapping, or not shimming at all?

Inquiring minds want to know.

SteveM

[tbone49]

Hi Steve, no shimming or lapping on my two you mentioned, or any others I know of. The hard thing might be finding some.

[Ralph]

My 1712 (the blue one in the Evelio Bling Bling thread) has BKLs and did not need to be shimmed. It will depend on the scope. Some scopes have more elevation adjustment than others. Mine is a Weaver T-24 and it adjusted fine. I used to have a Bushnell 4200 8-32X which didn't have enough elevation. I think that fixed power scopes offer more elevation adjustment than the variable powered ones.

[BlauBear]

We haven't caught the tall mount bug here yet, but I've never known a set of BKL's that needed lapping. It will be very sad for us if they really are out of business, though it does look that way. They could have increased prices 50% and still be my first choice.

[Jetmugg]

I already had the rings and risers, and mounted them up with a Weaver KT-15 last night. The rifle feels good with the higher rings, but I haven't had a chance to shoot it yet. Hopefully this weekend.

Thanks for sharing the tips.

SteveM.

[yankee]

Shimming and Lapping
Shimming between the base and the receiver is ususlly done to get more elevation for the scope. Many of the boosted scopes do not have as much elevation or windage so we had to shim the rear base to get more elevation. Or to get the scope tracking in the middle of it's range. The middle of the range is where they work best.
Lapping the rings is done to get the rings level. Meaning the part the scope sets in, front to back on both the front and rear ring. This is sometimes difficult to do or measure without dinging the scope. You may want to go to an automotive machine shop and get some plasti gauge. You then lay this in the base of the ring and then set the scope in place. Then press down and then remove the scope. If the small strips look the same width in both rings things should be about even. If they are tapered one way or the other the rings are not level and need to be lapped. Some cutters are made to lay in both rings then rotate till enough is taken out. Sometimes just 1 inch piece of stock can be laid in the rings with some girnding compound and work that in. The Burris signature Z ring with the plastic inserts eleminate all this lapping and some shimming and do not marr the scope. 20 years ago someone made some of these out of aluminium but I can't recall who.
Assuming the receiver is level and you shim the rear base you should have to do something with the rings.
If there was a leveling problem some gunsmiths would attach the scope to the rings then the rings to the bases and then put some accraglass under the base and lightly tighten the base on the receiver till dry. I never really did care for this. I also know of some that used the accraglass on the lower ring then set the scope on it. Don't forget the release agent

[Jetmugg]

With dovetail mounts, I've never figured out or seen anyone able to shim between the base and the receiver. If it's possible, that might certainly offer an improvement.

The only way I've seen something like BKL's shimmed are inside the bottom half of the ring. I am using such a setup on my CZ 452 with BKL rings. I have a couple thicknesses of a Busch can laid in the bottom half of the rear ring. This rifle is wearing a BSA scope, so I don't worry too much about giving it ring marks.

However, on my 1712, was using Eric Brooks adapters, and a set of Burris Sig Zee's with the offset inserts. I wanted to go higher, so I'm trying a set of high BKL's and BKL risers. This gives me about 1-1/4" between the top of the receiver and the bottom of the scope tube. If necessary, I will shim inside the rear ring - hopefully it won't need any shimming at all.

If it does need to be shimmed inside the rear ring, I have a tough time figuring out how it would be practical to lap the rings "on an angle" with the shim installed. The front of the shim would essentially be lapped away, while the rear of the shim would remain at its original thickness.

Has anyone lapped a set of rings with a shim installed in the bottom half of the rear ring?

SteveM.

[tbone49]

Hi Steve, don't buy trouble. I know several people who use Weavers and BKLs with no problem. I'm sure you will be fine.

[BlauBear]

If anyone's interested, I have a BKL one piece drop compensated set. Unfortunately, they're the kind that places places a solid beam over the ejection port and interferes with ejection on the 1712. They might work fine on a set of risers, but I never could find a use for them.

[Jason]

I can use that for my airgun, BB. PM me a price if you have time. Looks like I might not be getting my 1712 rebarreled anyway, as the engine in my truck just died and that's first priority, of course. Maybe getting a scope put on my airgun to practice with might give me a new "gun toy" as my wife calls them and make the hurt of not getting a new barrel go away. I swear, every time I am ready to rebarrel that thing, something else goes wrong. The first time, the transmission in my wife's minivan went out. The next time, something fell on our roof and we had to get that fixed. This time, the motor in my truck died. I was so close this time, too. I even went over to the gunsmith with a check in my hand to drop the rifle off and he wasn't in yet. Before I had a chance to try again, BAM. Either a rod or wrist pin went in the motor. Now I'm riding the motorcycle in 30-something degree weather to get to work.

[BlauBear]

I feel your pain. In my truck it was trash in the gas and then a leaky intake gasket. A new barrel is cheaper, too...