F
freebullet
Guest
That should be interesting, one way or another.
43-287B
- Thread starter Brad
- Start date
Did some shooting today. Lots to digest here. Not sure why the photos are rotated, all arerotated the same way.
All loads used a 44-287B cast from an alloy giving 22 BHn air cooled, aged over 3 months. All lubed with a version of SL 68B
21 gr H110, CCI 350
1328 fps, ES40, SD 14
18.7 gr N110, CCI 300
1229 fps, ES 38 SD 17
19.2 N110 CCI 300
1258 fps ES 40 SD 17
19.5 N110 CCI 300
1284 FPS ES 43 SD 16
19.8 N110 CCI 300
1313 fps ES 26 SD 11
All loads used a 44-287B cast from an alloy giving 22 BHn air cooled, aged over 3 months. All lubed with a version of SL 68B
21 gr H110, CCI 350
1328 fps, ES40, SD 14
18.7 gr N110, CCI 300
1229 fps, ES 38 SD 17
19.2 N110 CCI 300
1258 fps ES 40 SD 17
19.5 N110 CCI 300
1284 FPS ES 43 SD 16
19.8 N110 CCI 300
1313 fps ES 26 SD 11
Here are a few recovered bullets.
In the lower bullet it looks like the bands were smeared on one side of the bullet. This is very apparent as berm related damage when looking at the bullet. The next photo shows it more but doesn't show very well how much the lower section of the bullet based has been pushed downward by impact forces.
I was kinda shocked to see this dimple in the base of the bullet. The spruce cut must have left a bit of a cavity that pressure pushed the check into. Each bullet had the same dimple.
In the lower bullet it looks like the bands were smeared on one side of the bullet. This is very apparent as berm related damage when looking at the bullet. The next photo shows it more but doesn't show very well how much the lower section of the bullet based has been pushed downward by impact forces.
I was kinda shocked to see this dimple in the base of the bullet. The spruce cut must have left a bit of a cavity that pressure pushed the check into. Each bullet had the same dimple.
Bench set up is getting better. I need another bad with sand, the walnut media is too light and the bag under my elbow moves on me.
I feel like the gun wants to shoot but I'm not doing my share. I focused today on removing my hand after each shot and holding the gun much more loosely. I also tried to put as little pressure as possible on the grip with my off hand. A few times I caught myself letting part of my offhand contact the sandbag under my wrists and that gave me some vertical.
I liked the N110 loads but don't have lots of that powder left. It will get more time for certain.
The 21 gr H110 load showed a bunch of vertical. Some of that was me. I fired 2 five round strings and the impact point for the second was lower than the first. Each group on it's own was around 4 inches.
I feel like the gun wants to shoot but I'm not doing my share. I focused today on removing my hand after each shot and holding the gun much more loosely. I also tried to put as little pressure as possible on the grip with my off hand. A few times I caught myself letting part of my offhand contact the sandbag under my wrists and that gave me some vertical.
I liked the N110 loads but don't have lots of that powder left. It will get more time for certain.
The 21 gr H110 load showed a bunch of vertical. Some of that was me. I fired 2 five round strings and the impact point for the second was lower than the first. Each group on it's own was around 4 inches.
I need to get better photos up. The entire base section of that bullet is skewed that way. Think of taking a rectangle and pushing on top to make a trapezoid.
The other bullets I recovered show no signs of differential lube groove closure that I can see.
So, is it damage from the forcing cone? How do I test for that? I could mark the checks on the bottom, index at loading and chambering, and then see if I can recover them and find a consistent problem?
With as off kilter as the base is I would expect horrible accuracy of that deformation occurred in the chamber or barrel. With the muzzle pressure these loads have the bullet would, I presume, get blown off path pretty wildly. By 100 yards I would expect far worse accuracy.
I just don't know?
The other bullets I recovered show no signs of differential lube groove closure that I can see.
So, is it damage from the forcing cone? How do I test for that? I could mark the checks on the bottom, index at loading and chambering, and then see if I can recover them and find a consistent problem?
With as off kilter as the base is I would expect horrible accuracy of that deformation occurred in the chamber or barrel. With the muzzle pressure these loads have the bullet would, I presume, get blown off path pretty wildly. By 100 yards I would expect far worse accuracy.
I just don't know?
Ian
Notorious member
Lube grooves almost completely blown up to groove size from heavily-flowing alloy might explain a lot. Brad, if you mark and index bullets, you may be surprised how much slant a base can sustain and the bullets still group reasonably together, so don't discount them being so slanted leaving the muzzle. Same thing with a slanted crown. Some of the deck-o-cards shape shift there may have been berm damage, but that's not what filled in the lube grooves completely on one side and only "almost completely" on the other, THAT is happening either in the cylinder (chamber forcing cone) or the barrel forcing cone.
If you could get a load that wouldn't pound the bullet into oblivion it may stop doing that sideways smear
.....or you may have a serious timing issue or a hand that's kicking out under pressure and letting the cylinder slip.
If you could get a load that wouldn't pound the bullet into oblivion it may stop doing that sideways smear
.....or you may have a serious timing issue or a hand that's kicking out under pressure and letting the cylinder slip.
Last edited:
I realize this bullet is a bit crooked but it shows how much bullet is still in the cylinder throats when the nose first contacts rifling. The bullets are a very snug slip fit in the throats so I don't know how much they can get off kilter at this point.
I do have a big question, something I had not thought of before. Could I be seeing a bit of riveting? Is a small amount of material trying to flow into the forcing cone under pressure? As the bullet goes further down the bore it irons out but not evenly?
The nose shape means the bullet impacts the rifling suddenly rather than gradually. Is that enough to slow forward momentum of the nose while the base continues forward? Even a thousandth of an inch growth into the forcing cone could lead to the type of issues the bullets seem to show.
Would a higher tin alloy reduce this deformation? Less flow under pressure? The alloy used today was higher in Sb than in Sn, antimony wash was pretty noticeable in the bore after firing.
Something to ponder.
Ian
Notorious member
The humongous, beefy nose band has no relief grooves to allow metal to displace, so the whole thing goes into a plastic state as the solid nose takes the rifling. Right then the bullet is bisecting the cylinder gap, so no doubt it is wadding up and getting that over-40 spare tire in the middle. Then the bullet is literally extruded through the forcing cone, and you get what you're getting. That doesn't explain why there is so much off-axis deformation, but it might explain the cause of the extreme deformation in the first place.
That's why I suggested lathing a big vee-groove in the middle nose band of a few and seeing if that doesn't stop the entire bullet from going plastic. If you can make strain-break areas, like tall driving bands which can deform locally without making metal flow through the core of the bullet, then it might reduce the engraving pressure and thus the resistance so that the base can keep moving without piling the middle of the bullet up in the gap.
That's why I suggested lathing a big vee-groove in the middle nose band of a few and seeing if that doesn't stop the entire bullet from going plastic. If you can make strain-break areas, like tall driving bands which can deform locally without making metal flow through the core of the bullet, then it might reduce the engraving pressure and thus the resistance so that the base can keep moving without piling the middle of the bullet up in the gap.
Like this Ian?
I used my cutoff blade as it was the one tool I had right now that would cut that close to the chuck.
Groove is .092 wide and .007 deep.
Bullets will be sized to .432+ and groove is .418.
Should give enough room for metal displacement. The Barnes X bullets have grooves that are bore diameter. I haven't measured my bore diameter so I don't know I am that deep but I am sure this is enough to let metal move. I recut 5 of them to a .408 groove, way deeper than required but it will give a worst case scenario.
I did 15 bullets. Will run 15 with and 15 without with same loads.
And yes, I know that the bullet with the groove cut in the nose has a mark from moving when the mould opened. That will largely go away on sizing and is less of a flaw than the photo makes it look to be. Photos like that always exacerbate flaws.
I used my cutoff blade as it was the one tool I had right now that would cut that close to the chuck.
Groove is .092 wide and .007 deep.
Bullets will be sized to .432+ and groove is .418.
Should give enough room for metal displacement. The Barnes X bullets have grooves that are bore diameter. I haven't measured my bore diameter so I don't know I am that deep but I am sure this is enough to let metal move. I recut 5 of them to a .408 groove, way deeper than required but it will give a worst case scenario.
I did 15 bullets. Will run 15 with and 15 without with same loads.
And yes, I know that the bullet with the groove cut in the nose has a mark from moving when the mould opened. That will largely go away on sizing and is less of a flaw than the photo makes it look to be. Photos like that always exacerbate flaws.
Last edited:
fiver
Well-Known Member
I skipped a little bit of the conversation.
your chrono speeds are not indicating an issue there that would contribute to vertical stringing.
something that might help is shrinking the pictures from the previous groups and placing them side by side with these groups so we can compare the progress.
as far as the riveting thing.
that's a possibility, the lead on the gas check would indicate that.
how to tell or work around that?
change the pressure timing, or top pressure under time.
maybe a diameter change.
I would be more inclined to investigate the stringing than anything else right now.
your just THAT,,,,,,,,,, far away from putting up some good groups.
scope mirage?
elbow pressure.
grip change.
neck tension/crimp.
all the groups over 1300 show the stringing, but if you take that stringing out you have rifle groups there.
I would start at neck tension and try again at the top load only and put more shots on paper.
maybe bump the bullet another .001 in diameter to help the tension out.
I don't know if you have been following me and Poppers conversation on the Cu/Zn alloy or not but there is some good information there on how an alloy reacts to pressure and might give you something to think about.
your chrono speeds are not indicating an issue there that would contribute to vertical stringing.
something that might help is shrinking the pictures from the previous groups and placing them side by side with these groups so we can compare the progress.
as far as the riveting thing.
that's a possibility, the lead on the gas check would indicate that.
how to tell or work around that?
change the pressure timing, or top pressure under time.
maybe a diameter change.
I would be more inclined to investigate the stringing than anything else right now.
your just THAT,,,,,,,,,, far away from putting up some good groups.
scope mirage?
elbow pressure.
grip change.
neck tension/crimp.
all the groups over 1300 show the stringing, but if you take that stringing out you have rifle groups there.
I would start at neck tension and try again at the top load only and put more shots on paper.
maybe bump the bullet another .001 in diameter to help the tension out.
I don't know if you have been following me and Poppers conversation on the Cu/Zn alloy or not but there is some good information there on how an alloy reacts to pressure and might give you something to think about.
I do think a bunch of the vertical is ME. I have some things I need to work on and some changes to make in bench set up.
Things are coming together, or at least I feel that way.
Diameter change is possible but it must be down, not up. These are already a snug fit in the throats, any bigger and they won't chamber at all.
Things are coming together, or at least I feel that way.
Diameter change is possible but it must be down, not up. These are already a snug fit in the throats, any bigger and they won't chamber at all.
Ian
Notorious member
I was thinking deeper than wide, like a thread, but that should work well enough to prove/disprove the theory that nose extrusion and force required to do that is pushing bullet internal PSI to the point it just turns to pudding and squirts everywhere.
Your alloy is 22 bhn and powder charge backed off, I bet a Keith SWC wouldn't do what those are doing because it can engrave and squeeze into the bore with only metal in the outer parts of the driving bands displacing metal locally, not forcing the whole bullet to structurally crush. Rick and Jim both used clip-on WW +2% tin IIRC for their 44 Magnum bullets, and heat treat them a little. That alloy should be approximately equal tin and antimony and won't turn to liquid quite as easily or all at once, maybe adding tin will help your situation. Having that big, wide, custom-fit nose out front there and your custom-length brass is all designed to keep the bullet straight and guide it, but with the system you got right now all that is defeated because the alloy is too soft to resist the forces acting on it and the whole bullet shape is being compromised.
4.5" repeatable groups with several different loads is definitely getting close, most people would be happy with that at 25 yards. If you can get the bullet/alloy/powder combo to work together better you might be shooting ragged holes soon. One thing is for sure, the groups have been getting better every time you go to the range.
Your alloy is 22 bhn and powder charge backed off, I bet a Keith SWC wouldn't do what those are doing because it can engrave and squeeze into the bore with only metal in the outer parts of the driving bands displacing metal locally, not forcing the whole bullet to structurally crush. Rick and Jim both used clip-on WW +2% tin IIRC for their 44 Magnum bullets, and heat treat them a little. That alloy should be approximately equal tin and antimony and won't turn to liquid quite as easily or all at once, maybe adding tin will help your situation. Having that big, wide, custom-fit nose out front there and your custom-length brass is all designed to keep the bullet straight and guide it, but with the system you got right now all that is defeated because the alloy is too soft to resist the forces acting on it and the whole bullet shape is being compromised.
4.5" repeatable groups with several different loads is definitely getting close, most people would be happy with that at 25 yards. If you can get the bullet/alloy/powder combo to work together better you might be shooting ragged holes soon. One thing is for sure, the groups have been getting better every time you go to the range.
Measure the bore, groove depth and rifling height. I'm not reading back through 330 posts to see what the sized diameter and throats measure but if there is no restriction in the bore the only pressure increase would be engraving, can't see riveting from that. If it would why only on this bullet and no others?
Try sizing a half to a thousandths smaller. Should be a mild slip fit, not needing forced into the throats. You like making sizing dies, make one that fits "your" alloy this way.
Ask ANY bench rest shooter if the crown being square matters. As off as the bullet bases in your pictures appear to be if they were coming out of the barrel that way you well could hit the birm but it won't be a birm on the range your shooting at.
The vertical stringing could well be grip and/or follow through. A few thousands of an inch different muzzle position between shots is at least a few inches at 100 yards. Taking it out to shoot once every 5-6 months won't fix that.
.
Try sizing a half to a thousandths smaller. Should be a mild slip fit, not needing forced into the throats. You like making sizing dies, make one that fits "your" alloy this way.
Ask ANY bench rest shooter if the crown being square matters. As off as the bullet bases in your pictures appear to be if they were coming out of the barrel that way you well could hit the birm but it won't be a birm on the range your shooting at.
The vertical stringing could well be grip and/or follow through. A few thousands of an inch different muzzle position between shots is at least a few inches at 100 yards. Taking it out to shoot once every 5-6 months won't fix that.
.
They were a snug fit in the throats as much from lack of cylinder cleaning as anything. That was taken care of today. I need to clean it each trip I suppose. Bullets are sized to .432+. They slip into the throats with little finger pressure but won't fall thru under gravity. I have a slightly smaller sizer I can try.
I am thinking of taking a little thing of powder with me to the range. As my hand gets sweaty I change my grip some. Keeping it dry would help with consistency. Using the factory grip has made a difference too, it is far more comfortable to shoot now.
I am thinking of taking a little thing of powder with me to the range. As my hand gets sweaty I change my grip some. Keeping it dry would help with consistency. Using the factory grip has made a difference too, it is far more comfortable to shoot now.
F
freebullet
Guest
Just a thought...
hollow pointing might help this design. Thinking, shifting the center of balance back could be an improvement.
hollow pointing might help this design. Thinking, shifting the center of balance back could be an improvement.
That could well be a worthwhile test. I would suggest hollow pointing enough on the lathe to test and if successful send the mold off to Erik. In addition to shifting the weight to the rear it's possible that if there is a problem with no place for lead to move to it could give it a place. See? That's why freebullet makes the big money.
.