Markbo
07-17-2008, 12:33 PM
I have posted this report on single-actions already, but thought I would try here too. A little background: I bought a used BFR in .475 earlier this year. Shot only factory ammo from 320gr(?) up to 380gr ammo. The seller told me that it shot the heavier ammo well, but the lighter ammo not so well. I found it did not shoot the lighter factory ammo very well at all - like 4-5" groups @ 25 yards.
So recently, my friend Axehandle supplied me with some beautiful 475gr bullets:
http://i189.photobucket.com/albums/z110/agb1368/005-7.jpg
I have been waiting to make this trip. With much excitement and much care, I made up 7 different loads with the 24 hard cast 475gr bullets Axe was kind enough to send me.
I laid everything out, got all set up and promptly dropped my ammo box face down... and most of the carefully segregated and marked loads fell helter skelter on the ground. Not all of them - there were still a few stuck in their little holes. I shot 2 shots each of a couple of light loads first: 9.3gr W231 and 9.3 Titegroup. Can't tell much with 2 shot groups, but they were a pleasure to shoot!
Then I thought I would try some of the warmer loads that were still in the box... ones and twos. The rest would be pure guesswork. I moved up to 22.3gr LiL Gun and 19.3gr H110. These were not the hottest loads I had by far, but the same thing happened each time I shot one of these. The gun locked up. It was not bullet jump. The case set back slightly from the cylinder and it would not turn just cocking the hammer. I could force it, but was resistant to do so. I could tell the case was ever so slightly out of the countersink, but they would NOT be driven out with the ejector rod. In fact I bent the head on it try to bang one out. Luckily I had my handy dandy wooden dowel and had to smack the crap out of it with a screwdriver handle to get them out.
You can see visibly about 6mm up from the base the brass is bare - untouched. But above that you can see the case made contact all the way up the case and there are VERY fine longetudinal scratches - it looks almost like it was held and pulled lightly through 1000grit sandpaper. The cases are shinier right at that 6mm spot near the case head where there is more scratching. The harder I had to bang them out, the more visible the scratches and they are not even all the way around on all of them. On a couple I can see them clearly on one side and none on the other side, on other I can see them all the way round. On the light loads, I didn't notice that at all. I measured unfired cases at that point and they are .500".. perfect. The fired ones are .5095". Is that way too much?
Is it possible that the cylinder chambers are too large? Or not round? I don't have a set of precision pin gauges to measure them and I have never had much luck with the adjustable ball type. FWIW the cylinder was perfectly clean... no lead build up at the mouth or anything like that. Visually it looks fine. The loads are definitely not too long. Everything I have shot before now was with 320-380gr loads and nothing like this ever happened.
Any ideas? Also what should I do with these mixed loads? Go ahead and shoot them or pull the bullets and make them over again? Here are all the loads I made
Fired: W231 - 9.3gr, Titegroup - 9.3gr, Lil Gun - 22.3gr
Not fired: Lil Gun - 24.8gr, H110 - 19.3gr & 23.9gr
The unfired loads are not segregated... what is left is all mixed up. This is definitely a first for me, so I'd appreciate any advice. Just an aside, one thing I noticed is that every load shot WAY high with the rear sight bottomed out. If I can get it shooting I am gonna need a taller front sight!
Many thanks
Mark
So recently, my friend Axehandle supplied me with some beautiful 475gr bullets:
http://i189.photobucket.com/albums/z110/agb1368/005-7.jpg
I have been waiting to make this trip. With much excitement and much care, I made up 7 different loads with the 24 hard cast 475gr bullets Axe was kind enough to send me.
I laid everything out, got all set up and promptly dropped my ammo box face down... and most of the carefully segregated and marked loads fell helter skelter on the ground. Not all of them - there were still a few stuck in their little holes. I shot 2 shots each of a couple of light loads first: 9.3gr W231 and 9.3 Titegroup. Can't tell much with 2 shot groups, but they were a pleasure to shoot!
Then I thought I would try some of the warmer loads that were still in the box... ones and twos. The rest would be pure guesswork. I moved up to 22.3gr LiL Gun and 19.3gr H110. These were not the hottest loads I had by far, but the same thing happened each time I shot one of these. The gun locked up. It was not bullet jump. The case set back slightly from the cylinder and it would not turn just cocking the hammer. I could force it, but was resistant to do so. I could tell the case was ever so slightly out of the countersink, but they would NOT be driven out with the ejector rod. In fact I bent the head on it try to bang one out. Luckily I had my handy dandy wooden dowel and had to smack the crap out of it with a screwdriver handle to get them out.
You can see visibly about 6mm up from the base the brass is bare - untouched. But above that you can see the case made contact all the way up the case and there are VERY fine longetudinal scratches - it looks almost like it was held and pulled lightly through 1000grit sandpaper. The cases are shinier right at that 6mm spot near the case head where there is more scratching. The harder I had to bang them out, the more visible the scratches and they are not even all the way around on all of them. On a couple I can see them clearly on one side and none on the other side, on other I can see them all the way round. On the light loads, I didn't notice that at all. I measured unfired cases at that point and they are .500".. perfect. The fired ones are .5095". Is that way too much?
Is it possible that the cylinder chambers are too large? Or not round? I don't have a set of precision pin gauges to measure them and I have never had much luck with the adjustable ball type. FWIW the cylinder was perfectly clean... no lead build up at the mouth or anything like that. Visually it looks fine. The loads are definitely not too long. Everything I have shot before now was with 320-380gr loads and nothing like this ever happened.
Any ideas? Also what should I do with these mixed loads? Go ahead and shoot them or pull the bullets and make them over again? Here are all the loads I made
Fired: W231 - 9.3gr, Titegroup - 9.3gr, Lil Gun - 22.3gr
Not fired: Lil Gun - 24.8gr, H110 - 19.3gr & 23.9gr
The unfired loads are not segregated... what is left is all mixed up. This is definitely a first for me, so I'd appreciate any advice. Just an aside, one thing I noticed is that every load shot WAY high with the rear sight bottomed out. If I can get it shooting I am gonna need a taller front sight!
Many thanks
Mark