OK, after the last range session I mentioned that the 30BR was not "riding the bags" well. The front bag works great since I upgraded to a leather bag, but the rear bag moved 1/4" after every shot. That's not good when you are shooting "free recoil." It also left my shoulder black and blue after only 41 shots.
I realize that everyone wants me to try their favorite alloy, lube, bullet design, coating method, etc., and I hope to eventually play with all those variables, but ... one thing at a time. And today that one thing was improving my benchrest technique with the 30BR.
Here's one problem. The rear bag is a very good Protektor bag with 3/8" spacing between the ears. That's not quite enough space for my chubby Richard's Microfit stock. Oh, I can force the stock down into the bag, but it's such a tight fit that there's a lot of friction when it recoils back ... and the friction moves the bag.
Here's some suggestions I found on various forums:
-- obviously the bag should fit the stock, or visa versa.
-- place an anti-slip mat between the bag and the bench
-- place sanding screen between the bag and the bench
-- use velcro to keep the bag from moving
-- dampen the bench before setting the bag down (apparently a common practice in competition)
-- apply self-adhesive teflon or UHMW tape to the toe of the stock to reduce friction
-- place a microfiber cloth between the stock and the bag to reduce friction
I debated whether to order a custom bag to fit my chubby stock, or to reshape the stock to fit my bag. Custom bags are expensive and this stock is cheap as benchrest stocks go, so I decided to modify the stock.
The modified stock fit the bag much, much better.
While practicing sliding the stock back and forth on the bags, I noticed the bag rocked less if I flipped it around 180 degrees. I had been using the rear bag backwards because the chubby stock fit better that way. Now that the stock had gone on a diet, the bag could be spun back to its intended position.
Velcro, sanding screen, or anti-slip mat? After considering all three I tried an anti-slip mat because it was cheap and easy. It did indeed make it noticeably more difficult to slide the bag on the bench.
I do have some UHMW tape that I can try but that'll have to wait until I re-finish the stock. In the meantime I placed a thin microfiber cloth (the kind that comes with a new scope) between the stock and the bag.
Lastly, I increased the number of rubber bands on my "high tech return to battery system," up to 8 sets of rubber bands.
OK, let's see how it shoots with the new setup. I used exactly the same load as last time, with the powder coated GC bullet. Groups were shot starting on the left and going to the right.
The first group showed some potential. The bag did not move at all. However, the rifle still jumped around more than I cared for -- the 8 rubber bands seemed to make it jump forward on the rebound. You know how you can tell by feel whether or not a shot was good? Well the shots just didn't feel right.
Also my shoulder continued to get slapped despite the extra rubber bands.
The stock does not have a recoil pad because I did not anticipate that the very heavy rifle would need a pad with the puny BR cartridges. But I was wrong.
"Free recoil" lets the stock get a running start at your shoulder.
So I improvised a recoil pad. That helped a lot.
For the final group (on the far right), I tried gripping the rifle instead of "free recoil." I was experimenting with different grips and one shot went wild that was surely my fault. It reminded me that it's much easier to shoot free recoil provided you can get the rifle to "ride the bags."
Continued in the next post ....