Pop quiz!
- Thread starter Ian
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Ian
Notorious member
Load "C". I had a sighter for this group also with a .4-grain lighter bullet but the barrel was hot so I fired it last, resulting in the low-left hit. There really are 10 other buller holes in the target, but several clusters of three in the same hole as is common with HV/PC groups.
358156 hp
At large, whereabouts unknown.
BTW, I think it's great that you're shooting 10 rd groups. Well, "B" is trying to shoot round groups, and "C" is still stringing vertically. Drop one shot from either group and they're both 2 inchers. It would be interesting to know what order the shots were fired in on both targets, but that's just my silly old number crunching side coming out again. You can tell they're close by looking at the diagonal shot dispersion. Without knowing the shot sequence this would be inconsequential.
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Ian
Notorious member
I would have to get to reading-glasses distance to place the order on many of the hits. One thing I can say is they are pretty random.
My vote for next try is harden the bullets a little. these were cast Friday a week ago and powder-coated Monday and air cooled. They measure about 12 bhn. The same load as the left target in the original post has been grouping sub-moa at this range with 14.5 bhn bullets and a different color of PC.
My vote for next try is harden the bullets a little. these were cast Friday a week ago and powder-coated Monday and air cooled. They measure about 12 bhn. The same load as the left target in the original post has been grouping sub-moa at this range with 14.5 bhn bullets and a different color of PC.
Ian
Notorious member
True, but I still enjoy splitting hairs. This is the LR-308 with the plastic receiver that flexes 3 MOA with the weight of my noggin on the stock. Shot from a makeshift, chest-high bench on stilts so I have to stand. Even the lightest load is crowding 2400 fps and the bullets are soft enough to knock the crap out of any animal out to 200 yards.
What I'm trying to do is learn something. This rifle was turning in impressive groups with Remington brass and slightly tougher bullets that were NOT weight-sorted, were coated in blue paint instead of red with gold metallic flakes. The military brass I'm using now has thicker necks and slightly less powder capacity, and creates slightly more neck tension. Group size tripled. Why?
First thing was to deal with overpressuring the softer alloy in the smaller case by reducing the powder charge. I immediately noticed some telltale stringing and was trying to see if I could get back into the sweet spot again just with powder charge adjustment. Now I'm thinking one of the other changes must be the problem. I know that the Remington brass and blue bullets with known-good powder charge doubled group size by dropping from 14.5 to 12.5 bhn (diluted alloy). So alloy is suspect #1, but could it still work with tuning? At this point I think it might if I tuned down a lot more on pressure, but these tests indicate I might have to go lower than I'm willing for this rifle's purpose. One more thing to try before I cast a new lot of bullets is reducing the neck tension of these military cases to what the Remington brass was giving me. Now that I have an indication of what powder charge to use that might be next.
What I'm trying to do is learn something. This rifle was turning in impressive groups with Remington brass and slightly tougher bullets that were NOT weight-sorted, were coated in blue paint instead of red with gold metallic flakes. The military brass I'm using now has thicker necks and slightly less powder capacity, and creates slightly more neck tension. Group size tripled. Why?
First thing was to deal with overpressuring the softer alloy in the smaller case by reducing the powder charge. I immediately noticed some telltale stringing and was trying to see if I could get back into the sweet spot again just with powder charge adjustment. Now I'm thinking one of the other changes must be the problem. I know that the Remington brass and blue bullets with known-good powder charge doubled group size by dropping from 14.5 to 12.5 bhn (diluted alloy). So alloy is suspect #1, but could it still work with tuning? At this point I think it might if I tuned down a lot more on pressure, but these tests indicate I might have to go lower than I'm willing for this rifle's purpose. One more thing to try before I cast a new lot of bullets is reducing the neck tension of these military cases to what the Remington brass was giving me. Now that I have an indication of what powder charge to use that might be next.
fiver
Well-Known Member
just a random thought.
but brass changes everything.
they are thicker,,, but where are they thicker?
everywhere? sort of more on one side? how about the web area?
I know this is more of a pain but you could do the good shot bad shot case sorting thing and re-run the test real quick.
I wouldn't count that horivertical group, I don't think it had anything to do with the ammo.
but brass changes everything.
they are thicker,,, but where are they thicker?
everywhere? sort of more on one side? how about the web area?
I know this is more of a pain but you could do the good shot bad shot case sorting thing and re-run the test real quick.
I wouldn't count that horivertical group, I don't think it had anything to do with the ammo.
Kevin Stenberg
Well-Known Member
Ian
Your "Soft diluted alloy" of 12.5 bhn. Was the alloy a bit softer than COWW?
Concerning PC colors. Do you find that some colors have an affect (either posative or negative) on accuracy? Or do you use color to differentiate one bullet type from another?
Your "Soft diluted alloy" of 12.5 bhn. Was the alloy a bit softer than COWW?
Concerning PC colors. Do you find that some colors have an affect (either posative or negative) on accuracy? Or do you use color to differentiate one bullet type from another?
Ian
Notorious member
Yes, a tiny bit softer than COWW with about 15% soft scrap added. The coating seems to slow the "air quench" so the bullets are a point or two softer than as-cast anyway. Plus, these are "green", in another week they'll be a touch harder.
I'm just starting out experimenting with colors, I doubt it makes much difference but this red paint has some fine gold flakes in it so it's not exactly the same as what I had been using. The red shot fine in my Socom and Blackouts but at very low speeds.
I'm just starting out experimenting with colors, I doubt it makes much difference but this red paint has some fine gold flakes in it so it's not exactly the same as what I had been using. The red shot fine in my Socom and Blackouts but at very low speeds.
Add some Cu to the alloy. And get an alloy lower! Pencil barrel doesn't help either. Harder bullets will elp but you want softer for expansion? I've used smokes red, black and HF red, no difference I can tell. Most of my cases are LC of various years, MG shot once + a few various range pickup.
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fiver
Well-Known Member
the xcb bullet was designed for the 30-06 with saami type throats.
it has some leeway to account for throat wear, but seems to shoot best if it is gently touching the lands or up close to them.
it will shoot just fine in the 308, as we have all seen, since their throat is similar so something like the 300 savage will also fall in line.
I don't think I could cast with mine if it were a 5 cavity mold, 2 is enough for a rifle mold I care about and expect something from.
it has some leeway to account for throat wear, but seems to shoot best if it is gently touching the lands or up close to them.
it will shoot just fine in the 308, as we have all seen, since their throat is similar so something like the 300 savage will also fall in line.
I don't think I could cast with mine if it were a 5 cavity mold, 2 is enough for a rifle mold I care about and expect something from.
Snakeoil
Well-Known Member
I don't think only 1 answer is correct. And I reached this conclusion before realizing how many answers were below the intial post.
I'd say the right answer is B and C. This is because the right target tightened up with 2.2 gr less. But it is not perfect. So, does it show that it is getting better and can get even better or does it show that it is better, but missed the sweet spot which is between the right and left target.
So, I would load 1 grain less than the right and I grain more than the right and see which one shows the best (if any) improvement.
I also might ask someone who is a better shot than me to shoot the load for the right target again to see if he could tighten them up a bit. ;-P
I'd say the right answer is B and C. This is because the right target tightened up with 2.2 gr less. But it is not perfect. So, does it show that it is getting better and can get even better or does it show that it is better, but missed the sweet spot which is between the right and left target.
So, I would load 1 grain less than the right and I grain more than the right and see which one shows the best (if any) improvement.
I also might ask someone who is a better shot than me to shoot the load for the right target again to see if he could tighten them up a bit. ;-P
F
freebullet
Guest
Just load a couple k of the right ones in post one
Ian
Notorious member
Maaaaan. I was gonna really impress you guys but I blew it. This is the same powder charge as the right target in the OP.
Ok, the bullets settled in somewhere around 14.5-9 bhn so I had another go, with a dirty bore that has had at least 50 rounds through it since last cleaning. First cold bore shot from a dirty barrel is usually a little off as this one is but from a clean barrel it usually goes on the group. Shot sequence is numbered, shot 9 I called due to shooter error on follow through and 10 jumped as the shot broke too due to trying too hard not to repeat #9. Bright sun beating down, sweat in eyes, all the usual excuses which is to say there's a good chance it wasn't the load unless it was simply alloy failure due to heat. The barrel and suppressor were HOT.
I didn't chronograph these but they should be around 2350 fps.
Ok, the bullets settled in somewhere around 14.5-9 bhn so I had another go, with a dirty bore that has had at least 50 rounds through it since last cleaning. First cold bore shot from a dirty barrel is usually a little off as this one is but from a clean barrel it usually goes on the group. Shot sequence is numbered, shot 9 I called due to shooter error on follow through and 10 jumped as the shot broke too due to trying too hard not to repeat #9. Bright sun beating down, sweat in eyes, all the usual excuses
which is to say there's a good chance it wasn't the load unless it was simply alloy failure due to heat. The barrel and suppressor were HOT.I didn't chronograph these but they should be around 2350 fps.
Pistolero
Well-Known Member
Well, if you are hunting mice, maybe you need to tighten that up a touch. Otherwise, I don't see
many deer or hogs slipping through the gaps in that group.
Hell even squirrels and rabbits, those are easy head shots.
Am I correct that those are 1/2 grid lines?
many deer or hogs slipping through the gaps in that group.
Hell even squirrels and rabbits, those are easy head shots.
Am I correct that those are 1/2 grid lines?
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