I have been reading up all the great information on hear and decided to start doing some trial and error on my rifle...
I have a stock Weatherby mk v ULW in 300 weatherby.
I used to shoot with harris swivel bipods but I read numerous posts that say bipods inhibit a rifles accuracy for numerous reasons. So I took them off.
I have also read that light contour barrels sometime benefit using a pressure point on the barrel and some react well with floating the barrel. A remedy that I wanted to try was to shim the action to allow for floating the barrel using a cut up hard plastic card. When doing this, the barrel raised slightly up but was stillin contact with the pressure points built in to the bell and carlson stock. Also, the stock hugs the barrel all the way down to the receiver on both sides. Even if I was able to take the pressure point out of the equation to try a floated barrel, it would not be floated due to the side walls of the stock touching the barrel throughout the entire length.
I took the shims out and went out to the range to see if it was more accurate without the bipods. Accuracy seemed to improve greatly at 100 and 300 yeards.
My question is as follows from where I can go from here:
1. Should the stock only be touching the barrel at the front pressure point at the tip of the stock for best accuracy?
2. Should I sand the side walls of the barrel channel so only the pressure point touches and try shooting it then?
3. Should I try shimming the action again to try a floated barrel to see if this is worth sanding the pressure poitn out permanently?
I would like to get this down to .5" grouping consistently. FYI - My dad handloads for me and I am shooting 180 gr accubonds with 80 grs. of H4831. We have also talked about increasing the OAL as weatherby puts a lof of head space in their chambers and also increasing powder charge to 82.5 grains as I have read numerous guys shooting this powder and charge and being the best pet load.
It is unclear as to how the rifle was configured when it shot well. Was it with a bipod or without a bipod?
Was the bipod on dirt or concrete?
I do not see any problem with increasing the COL as long as you do it with a moderate load and work up to max with that COL. I would not worry about magazine length as it is not a first priority to shoot twice. First priority is to shoot accurately once. I doubt that increasing COL will do a lot of good. It may do a little good, but with the amount of freebore in a Weatherby you will still have a long jump. A bullet with a long bearing surface will often times jump better than a short bullet.
There are rifles that do not shot accurately off of a bipod, particularly if the bipod is on a hard surface. You can see if it will shoot better in dirt. If it does not like to shoot well off of a bipod then it probably will not like a hard rest under the foreend either. The next time you go to the range take a folded up towel to rest the fore end on and see if groups improve.
I do not know anything about the plastic stocks but I would take all contact off the barrel except for the pressure points and see what that does for it. I would leave the pressure points alone until I was desperate.
I would not do the credit card trick except for a limited amount of testing. What you are doing is torquing the action to gain barrel clearance.
Only make one change at a time so you can tell what is happening.
I own 3 Weatherby's and have found that the lightweight barrels (use to be called buggy whips) shoot better with a pressure point against the barrel. Both shot worse freefloating for me. If you do the bedding yourself you fill in the flutes with moldeling clay around the area of your pressure point. Remove it when done.
The pressure point on my lightweight barrels is fairly substantial. Use of credit cards in this area or something equal to do the shimming with until it shoots well. This is the only area the stock touches other than the action.
I find a bullet and load to the velocity and consistancy I want then 'tune my rifle pressure point' using shims. From here I then put a permanant bedding pressure point. This is some old school stuff.
Both of my .257 Lgwghts shoot under 5/8" at 200 for 3 quick shots from a COLD barrel. 1st 2 shots cutting the 3rd at 11:00 form both rifles.
The Accumark's are free floating from the factory and shoot well that way. 7STW
I have heard that the pressure point is in the area 11-14# range from the factory FWIW. I do not know how to measure that. I could get the wife to hold scale steady enough while I pulled down on the barrel. (just kidding)