Author Topic: scope mount screw holes (Read 827 times)

quicksdraw45 · « **on:** May 17, 2003, 03:48:22 PM »

Mounted the scope on my 7 TCU barrel , I just about did not have enough adjustment to zero the scope it was so far out of line with the barrel . I thought maybe I didnt mount the scope properly so I redid it with the same results . I then bought a set of burris signiture zee rings and a weaver mount and used the shims for 30 inches at 100 yards and still had to use the scope adjustment to bring it 3 more inches to the right .
Final conclusion is the mount holes are so far out of line with the bore to create a 33 inch error at 100 yards .(not real happy with that)
First range report was 5 shot groups of 1 inch at 50 yards in the fire forming process using 26 grains of blc-2 and a elcheapo no name psp 150 grain bullets from the gun show, I see some good potential from this barrel !
Any body have a preferred bullet for target work with the 7 TCU 14 inch barrel ??

KYODE · « **Reply #1 on:** May 17, 2003, 05:29:50 PM »

don't have the 7tcu, but the first bullet i would try would be a 120gr nosler balistic tip. it shoots good in my 7-08. if it doesn't satisfy you then i'd try a sierra 130gr single shot pistol bullet or 120gr hornady v-max. these bullets should produce great accuracy, plus be suitable for hunting.

helobill · « **Reply #2 on:** May 17, 2003, 05:45:07 PM »

Quicksdraw,
If this is a new barrel, I'd be sending it back! Unless the scope is new also or not optically centered. If you're sure the scope is optically centered, try turning the scope 90 degress and see if it boresights just as far off high or low. If it's still saying off to the side, then you're right the holes are drilled out of line. 33" at 100 yards is a little over 1/2 a degree (1 minute of a degree is 1.04 inches at 100 yards) most gunsmiths are better than that. Signature rings or windage adjustable rings are probably your only choice.
Bill

coltfan · « **Reply #3 on:** May 17, 2003, 05:46:53 PM »

After finding a small dent in a scope I had mounted on another gun, I used the Burris Zee rings with the pos-align inserts to prevent damaging the tube on my new Burris 3 X 12. The added benifit of being able to get the scope closer to the center of the target without using the scope adjustments was an added benifit. But now that I have used this system, I'll never use anything else.

I'll second Kyode's nomination for the three bullets he listed. While I have not used them in the 7TCU, I am working with all three in my 7-30 Waters. So far I've had exceptional results with the 130 grain Sierra SSPB and 748 powder.

quicksdraw45 · « **Reply #4 on:** May 17, 2003, 07:15:31 PM »

This is a Gently used barrel I bought from ED, The scope is a new TC 3x9 pistol scope , The burris zee signiture rings were a fairly simple permanent fix for the problem but I just should have never had to do it .

SD Handgunner · « **Reply #5 on:** May 17, 2003, 10:11:47 PM »

Many years ago I had a similar problem. I thought it was the holes in the barrel that were off, but when my gunsmith checked it out for me, it was the Weaver Scope Base that was off.

Larry

quicksdraw45 · « **Reply #6 on:** May 18, 2003, 05:45:07 AM »

I am not sure who made the first mount I tried on this barrel but it was fine on a .223 barrel and a 357 max ,I then went to the weaver mount so I could use the burris Zee signiture rings for the adjustment. After almost the exact same results with 2 different mounts it makes me think it was the holes

SD Handgunner · « **Reply #7 on:** May 18, 2003, 06:04:24 AM »

YEP, if you used two different mounts I would have to agree that it is more than likely the holes drilled off center.

Larry

Bug · « **Reply #8 on:** May 26, 2003, 02:22:18 AM »

I've had this problem on rifles before, but thankfully not on a T/C barrel. As the T/C is cylindrical where the mount screws on, wouldn't this also induce some "twisting" in the scope? If you managed to get the mount down tight, the added height of the rings would accentuate the error, and put even more pressure on the scope. I can see where it would create some real problems, with POI shifting, when changing power. Doesn't this make sense to y'all?,,,,,,,,,,,,,,,,,,Bug.

quicksdraw45 · « **Reply #9 on:** May 26, 2003, 05:10:19 AM »

The Reason I picked the burris zee signiture rings is There statement that the synthetic pivoting inserts are stress free , scratch free . If you look at the design closely you will see how this works .
I have used this to mount 2 barrels so that I can use the synthetic pivoting shim system so that I am not using more than 5 MOA of scope adjustment , This way you also stay centered in the class and are not using the edge of lense in scope.