Forums.NitroExpress.com

500Grains - Will do. For "the record"...until very recently, I assumed I was the problem. After all the rifle shot like a house afire originally and nothing had changed as near as I could tell. I piled my sandbags higher, put 'em on top of a 6x6, always have kept my hand under the forend, tried lower bags, tried with and without the scope, tried with the bags under the receiver (hand still between the bags and forend), different powders, different primers & bullets, different seating depth, continued to shoot with S&B factory loads as a control...and probably other stuff that escapes my mind right now. I talked to JJ earlier today and he suspects that the replacement scope may have caused the crossing problem (more weight). I'm not sure, but in deference to his expertise, I'm going to wait until I get the Leupold back and put it back on the rifle and try it again.

I tried to get the rifle to regulate by using handloads. I continued to get closer to regulation, but not quite there. As I had to lower the powder to much lower levels than I expected, or thought reasonable, I began to suspect all was not well. Reloading books that have the 9.3x74R aren't all that common, but those that I have (and I have a bunch of 'em) all indicated that with a 24" barrel I should have been getting standard velocities (~2250 +/- fps) at powder levels as much as 8 grains more than I was using. Figuring that the manuals couldn't be THAT far off, I checked velocity over my chronograph (Oehler Model 35P). When I saw that my velocites were down to 1980, and STILL not preventing crossing, I figured I was on a fools errand with the reloads re: solving the problem. Reloading is not a stranger to me. I've got some 40+ years of it including making my own bullets (cast and jacketed), wildcat development, case forming, etc. I'm so deep into that game I had over 100 sets of dies on my bench and more than 100# of powder in storage. Sick...

I stepped back...said a few working words, and thought about where I was and where I had been with this rifle. When I combined the randomness of the "grouping", with what appeared to be crossing, as well as looking at that original group (I kept it on the wall above my bench to remind me of where I wanted to go) I knew (finally) that I might be part of the problem, but no way ALL of the problem. That's when I started shooting at 50 yards w/ & w/o scope and at 100 yards with a different scope.

I shoot the rifle at 50 yards without a scope using the open sights. My eyes aren't all that good anymore (diabetic w/ tri-focals), but I believe I was getting ~ 1" crossing at 50 yards. It was only a half dozen shots or so, but 1" cross at 50 would pretty easily translate to 2" at 100 yds, at least in my mind. That's why I'm wondering about JJ's suggestion that scope weight might have been the latest problem. I dunno...We'll see in the not too distant future I suspect. BTW - For those not familiar with diabetes...as my blood sugar level varies (goes up and down), the fluid pressure in my eyeballs also varies. As the pressure varies, my vision varies. As a result of this variation a pair of prescription glasses are really only "right" at a specific blood sugar level. I generally have my eyes tested early in the morning or late afternoon which is the best I can do for a normal sugar level that I can expect more often than not. My vision never goes away, but it can get sorta fuzzy at times which prevents me from seeing fine detail. That is the reason I gave up hunter benchrest shooting. I couldn't always see the rings or the bull in enough detail to be competitive! Anyway, this tutorial is now over & class dismissed.

I will try the hang and clang method

to see if perhaps the barrels have come "loose" but not separated enough that it can readily be seen. Per W. Moore request I've looked at the seams between barrels and rib (upper & lower) with a magnifying glass looking for any indication of separation...I didn't see anything, but then again...my eyes, etc.

In the meantime, I believe I'll try and find a good handload with velocities in the 2300 fps range. My goal will be to get as much velocity as I can get with pressures in the 40 - 42k psi range.
The Hodgden manual indicates that a compressed load of H4831 should give me roughly 2230 fps or so from a 24" barrel with pressures less than 40k psi. H4350 will get me a bit more velocity with a few grains less but at a higher pressure (~41k psi) . The Hodgden site also has the Winchester loading data and I accessed that data as well and it indicates that W760 would get me 2350 fps or so with pressures in the 40 kpsi range. I don't have any W760, but I do have quite a few pounds of H414 which is the same powder. This relaoding work will be to find "the load" for which the rifle will be re-regulated if that should become necessary.

I've vented enough...I'll check back to see if anybody comes up with something I haven't tried yet. Pilgrim