L Ross
Well-Known Member
It seems as though this topic belongs here but I didn't know if I should just tack it onto the slightly flawed vs visually good thread and decided it deserved its own thread.
In my key board ramblings earlier this week I mentioned my friend was disappointed with some groups he got while trying to shoot a CBA postal match 100 yd. score target. I thought his groups were fine and where typical of what we can expect from cast. After my friend, (Jon), really looked at his targets and, gasp!, took a ruler to them, he found that none of the two shot groups had even hit the two inch mark. The worst were 1.75" and three of five were an inch or less. I suggested he make the hour and a half drive to the Thorn Hollow Ballistic Research Facility on Friday and we'd have lunch and conduct some testing.
After a bowl of sweet and sour green bean soup, a Creeping Charlie dark brown ale, and 20 minutes of sitting quietly on the porch to let it settle, we repaired to the bench.
I had jury rigged an umbrella to shade the shooter and the shootin' shack cast just enough shade to protect the spotter. Prior to Jon's arrival I had painted and set up targets, both paper and steel. I had paper targets at 100 yards and that's where we started.
Most of Jon's postal matches are relatively short range so his load is a mild charge of 4227 in his custom .308 Springfield with a medium heavy barrel. He has some version of a Vortex scope with a 30 m/m tube and some kind of tactical reticle, but I know it is in inches not Mils. I can extrapolate his velocity is right around 1,400 fps with the Lee 312-155-2R he used on the postal score targets. Today he was testing the NOE XCB bullet. I know he water drops his bullets and shoots wheel weights with about 1 lb. of lino to 20 lbs. of WW, sizes to .311". He fired at 10 shot group, and though he took his time, I would not say he was particularly slow about it and by the time he finished the barrel was just a little too hot to comfortably touch. Jon was very pleased with his group of about 1.5". I don't have a photo of it, and he get the target for his records. He set the rifle aside to cool while I got a new zero because I had added a 20 MOA rail to my Remington having run out of elevation at 440 yard shooting last month.
I asked Jon if he had found time to load up a jacketed bullet test load to compare to his cast load and he had not had time. In the interest of science I had put together 10 of my best efforts and components with 168 Sierra Match King bullets I had gotten at a gun show in a box of stuff. I had put them In Lapua brass over 16.5 gr. of old H-2400 sparked off by CCI bench rest primers. I offered them to Jon and he accepted. Here may be where we went awry. We did not think to clean
the bore of the cast lube/fouling instead just shot the jacketed loads.
I had set up the target with two bullseye in a vertical format about 15" apart. The bulls are 2" stencils I spray paint onto white, unwaxed butcher paper. I keep a big roll in the shootin' shack. I staple these to Corfam backers that I paint white so the letter does not show through the butcher paper. 2020 will be a good year to score these Corfam backers as everybody, their brother and sister are running for political office and you can get these yard signs free gratis after the elections. They make excellent target backers, much better than card board and they are weather proof and sort of self healing to bullet holes. More so than the politicians anyway.
Okay, back to undrifting my thread. Jon's first shot was the most wonderful pin wheel I can remember seeing in a long time. We looked at one another and I was expecting to see the cast bullets get soundly trounced as Jon poured shot after Sierra shot through the same raggedy hole. Au contraire gentle reader, the SMK group rather sucked. It ended up about 2.5", although the last 5 may have been closer to 1.25" and thus my concern that perhaps we should have cleaned the bore. Feeling like had mucked that test up we moved on.
My 20 MOA rail had indeed raised my 100 yard point of impact about 20 inches above my point of aim. I rezeroed my scope, set a new zero on my turret. To my great relief the windage had not changed even a skosh from the two piece Weaver base to the Leupold one piece =20 MOA picatinny rail. I plinked a few targets at the 208 yard rail and Jon did the same.
After resetting the steel and placing a new paper target at 100, I set about to test the Lee bullet against the XCB bullet. This time I have photographic results. Even this test is flawed because I shot the Lee's at 1,450 fps and the XCB's at 1,750 fps. The reason is the faster load is dimpling my mild steel targets at my 80 yard off hand rail. Yet I want the faster, ballistically better XCB bullet for when I make my attempt to duplicate Walter's 5 into 10" at 500 feat, thus the +20 MOA rail also.
I shot the Lee's first and was pretty satisfied with ten shots at less than 1.7". After letting the barrel cool I shot the XCB load. The Lee's were fired from carefully prepped FC brass and used standard CCI 200 primers. The XCB's were in Lapua brass, with the CCI bench rest primers. Both sets of brass are sized in the RCBS Gold Medal X-die full length sizer with a .335" neck bushing. I visually inspected the bullets prior to seating them. They get sized to .311", wear Hornady gas checks, have Ben's Red in the groove and a light wash of BLL on them. I seat them so I see faint land marks on the ogive when I extract a loaded round.
The XCB load was really turning out a nice group and in the end 7 of the 10 shots were touching. Shot #9 will haunt me for a while.
This whole bench rest shooting is trickier than it looks. I was really in a groove with the rifle in its porcine 40-X stock riding straight back in recoil, until, #9. Darn it anyway, the bags were crawling around on the bench and I was repositioning the rifle between shots so it was pretty well aligned with the bull with minimal input from me, then wrapping myself around the rifle and squeezing off each shot, until #9. I used the thumb of my left hand near the toe of the stock, just ahead of the rabbit eared bag to gently hold the cross hairs on the center of the bull and on firing felt the recoil push the stock ever so slightly toward my shoulder knuckle instead of straight back into the pocket. Jon, on the spotting scope, said, "There's your flyer!" #10 went right back into the torn area that ultimately held 7 bullets.
I never knew or would have believed how sensitive a rifle can be. I felt the stock recoil away from the thumb pressure! How in bloody helmet, do shooters like Walter's brother hit targets at 1 mile from an improvised rest shooting prone? How?
Well I'll try to stick the pictures on this post for your scrutiny or screwtinny. All of you have a splendid Sunday. Too hot and humid to shoot today. I think an early MC ride and more reloading are today's agenda.
In my key board ramblings earlier this week I mentioned my friend was disappointed with some groups he got while trying to shoot a CBA postal match 100 yd. score target. I thought his groups were fine and where typical of what we can expect from cast. After my friend, (Jon), really looked at his targets and, gasp!, took a ruler to them, he found that none of the two shot groups had even hit the two inch mark. The worst were 1.75" and three of five were an inch or less. I suggested he make the hour and a half drive to the Thorn Hollow Ballistic Research Facility on Friday and we'd have lunch and conduct some testing.
After a bowl of sweet and sour green bean soup, a Creeping Charlie dark brown ale, and 20 minutes of sitting quietly on the porch to let it settle, we repaired to the bench.
I had jury rigged an umbrella to shade the shooter and the shootin' shack cast just enough shade to protect the spotter. Prior to Jon's arrival I had painted and set up targets, both paper and steel. I had paper targets at 100 yards and that's where we started.
Most of Jon's postal matches are relatively short range so his load is a mild charge of 4227 in his custom .308 Springfield with a medium heavy barrel. He has some version of a Vortex scope with a 30 m/m tube and some kind of tactical reticle, but I know it is in inches not Mils. I can extrapolate his velocity is right around 1,400 fps with the Lee 312-155-2R he used on the postal score targets. Today he was testing the NOE XCB bullet. I know he water drops his bullets and shoots wheel weights with about 1 lb. of lino to 20 lbs. of WW, sizes to .311". He fired at 10 shot group, and though he took his time, I would not say he was particularly slow about it and by the time he finished the barrel was just a little too hot to comfortably touch. Jon was very pleased with his group of about 1.5". I don't have a photo of it, and he get the target for his records. He set the rifle aside to cool while I got a new zero because I had added a 20 MOA rail to my Remington having run out of elevation at 440 yard shooting last month.
I asked Jon if he had found time to load up a jacketed bullet test load to compare to his cast load and he had not had time. In the interest of science I had put together 10 of my best efforts and components with 168 Sierra Match King bullets I had gotten at a gun show in a box of stuff. I had put them In Lapua brass over 16.5 gr. of old H-2400 sparked off by CCI bench rest primers. I offered them to Jon and he accepted. Here may be where we went awry. We did not think to clean
the bore of the cast lube/fouling instead just shot the jacketed loads.
I had set up the target with two bullseye in a vertical format about 15" apart. The bulls are 2" stencils I spray paint onto white, unwaxed butcher paper. I keep a big roll in the shootin' shack. I staple these to Corfam backers that I paint white so the letter does not show through the butcher paper. 2020 will be a good year to score these Corfam backers as everybody, their brother and sister are running for political office and you can get these yard signs free gratis after the elections. They make excellent target backers, much better than card board and they are weather proof and sort of self healing to bullet holes. More so than the politicians anyway.
Okay, back to undrifting my thread. Jon's first shot was the most wonderful pin wheel I can remember seeing in a long time. We looked at one another and I was expecting to see the cast bullets get soundly trounced as Jon poured shot after Sierra shot through the same raggedy hole. Au contraire gentle reader, the SMK group rather sucked. It ended up about 2.5", although the last 5 may have been closer to 1.25" and thus my concern that perhaps we should have cleaned the bore. Feeling like had mucked that test up we moved on.
My 20 MOA rail had indeed raised my 100 yard point of impact about 20 inches above my point of aim. I rezeroed my scope, set a new zero on my turret. To my great relief the windage had not changed even a skosh from the two piece Weaver base to the Leupold one piece =20 MOA picatinny rail. I plinked a few targets at the 208 yard rail and Jon did the same.
After resetting the steel and placing a new paper target at 100, I set about to test the Lee bullet against the XCB bullet. This time I have photographic results. Even this test is flawed because I shot the Lee's at 1,450 fps and the XCB's at 1,750 fps. The reason is the faster load is dimpling my mild steel targets at my 80 yard off hand rail. Yet I want the faster, ballistically better XCB bullet for when I make my attempt to duplicate Walter's 5 into 10" at 500 feat, thus the +20 MOA rail also.
I shot the Lee's first and was pretty satisfied with ten shots at less than 1.7". After letting the barrel cool I shot the XCB load. The Lee's were fired from carefully prepped FC brass and used standard CCI 200 primers. The XCB's were in Lapua brass, with the CCI bench rest primers. Both sets of brass are sized in the RCBS Gold Medal X-die full length sizer with a .335" neck bushing. I visually inspected the bullets prior to seating them. They get sized to .311", wear Hornady gas checks, have Ben's Red in the groove and a light wash of BLL on them. I seat them so I see faint land marks on the ogive when I extract a loaded round.
The XCB load was really turning out a nice group and in the end 7 of the 10 shots were touching. Shot #9 will haunt me for a while.
This whole bench rest shooting is trickier than it looks. I was really in a groove with the rifle in its porcine 40-X stock riding straight back in recoil, until, #9. Darn it anyway, the bags were crawling around on the bench and I was repositioning the rifle between shots so it was pretty well aligned with the bull with minimal input from me, then wrapping myself around the rifle and squeezing off each shot, until #9. I used the thumb of my left hand near the toe of the stock, just ahead of the rabbit eared bag to gently hold the cross hairs on the center of the bull and on firing felt the recoil push the stock ever so slightly toward my shoulder knuckle instead of straight back into the pocket. Jon, on the spotting scope, said, "There's your flyer!" #10 went right back into the torn area that ultimately held 7 bullets.
I never knew or would have believed how sensitive a rifle can be. I felt the stock recoil away from the thumb pressure! How in bloody helmet, do shooters like Walter's brother hit targets at 1 mile from an improvised rest shooting prone? How?
Well I'll try to stick the pictures on this post for your scrutiny or screwtinny. All of you have a splendid Sunday. Too hot and humid to shoot today. I think an early MC ride and more reloading are today's agenda.
