Brownells Gunsmith Tech Corner - July 2008

Question: I recently went to the range to shoot my newly purchased Savage model 12 F-Class in 6.5x284 Norma. I had mounted a new scope and bore-sighted the rifle. At 50 yards my shots were nowhere near the target, nor were they at 25 yards. By watching the dirt behind the target frame I discovered the bullets were impacting way to the left.

At home I mounted an old scope I knew was OK, and bore-sighted the rifle. At the 50 yard range I mounted 2 rows of 5 targets each and shot at the middle of the rows. Didn't hit the paper. I had the same problem. Knowing what had happened the last time, I adjusted the cross hairs to bring the bullet impact to the right, eventually into the bull of the aim point.

When I got home I bore-sighted to rifle and compared that to where to crosshairs were pointing. At 15 yards the crosshairs were, as best as I could judge because of parallax, approximately 9 inches to the left of where the barrel was pointing! This equates to 28 - 30 inches at 50 yards! HELP!

I am shooting 142 grain Sierra Match Kings, seated to barely touch the rifling. The bullet is gripped by half the length of the neck, about .125 inch, and the powder charge is not excessive; 47 grains of Hodgdon Hybrid 100V and 50 grains of Vihtavuori N165. At 50 yards both loads impact the target at the same place.

Answer: It sounds like an alignment issue. Check the scope to see if the tube runs parallel with the bolt body. Hopefully it's that simple. However, it could lie with the mounts and/or their holes in the receiver, or possibly the barrel threads were not cut properly and are positioning the barrel off to the side. If this is the case I would be very tempted to return the gun to the factory for service. -- Steve Ostrem, Brownells Gun Tech


Question: I am attempting to install one of your Chapman 2 position safeties (#201-100-098) in a Mauser bolt shroud. The bold shroud is extremely hard to the point of being impossible to drill. How do you recommend "softening" the shroud so that it can be machined?

Answer: Drawing the temper on the rear of the shroud is a good idea and easy to do. Heat it up until the metal turns purple or even a little more and it will drill easily. Just heat the rear portion wear the drilling and milling needs to be done. -- Steve Ostrem, Brownells Gun Tech


Question: What size barrel link would work on a Springfield ULTRA compact slide on a Caspian frame? I tried a .273 and it wont link down to clear the lugs. The barrel is Springfield’s Bull. Ramped of course. The ramp cut in the slide I made .005 wider. It does not bind so far as I can tell. With the slide stop removed I can cycle rounds thru the gun just fine. So it seems a shorter link would be in order.

Answer: The link you select will depend on the fit of your barrel. The link of the correct length will meet the following criteria: Hold the barrel in your hand with the link and link pin installed. Slip the slide stop through the link ands press the slide stop pin back into the radius of the barrel lugs (this is the position the slide stop will be when the barrel is installed in the slide and in battery). With the slide stop pin held firmly in the radius of the barrel lug, you should be able to move the link ever so slightly on the slide stop pin. That is to say the hole in the link should not contact the link pin at the top or bottom while the slide stop is firmly contacting the lug radius. Every once in a while the barrel fit is such that you are "in between" 2 links (hits on the top inside of the pin hole on the short link, than hits on the top of the hole with the next sized link). In that case you may have to egg out the hole slightly. -- Eric Kiesler, Brownells Gun Tech