As title says I'm looking for experience people have with commercial PC bullets in rifle calibers ? Good/bad anything. I was looking at 8mm Mauser commercial PC lead bullets (BNH 20) and thought I'd ask advice here before committing. Do I use lead recipes or can I push it all the way to FMJ (since it's PC-ed and 20 bnh). Is 20 bnh way too hard ?
Commerical Rifle PC experience
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pushing cast/coated bullet to fmj velocities
No experience with commercial pc'd bullets. I have been experimenting with my own cast/coated bullets.
Home cast/home coated/home made gas checks
A link to alloys and the pressures they are used for.
Cast bullet reference on lead alloy's, min / max pressure, lube, shrinkage,
There are 2 main coating being used right now:
Commercial ='s hi-tech/polyurathane
Home ='s dry powdercoat powder/polyester
Bullet size/design:
Anything under pressure will go to the least point of resistance. Add to that the fact that your asking a lead bullet to be under pressure, have the front 1/2 (nose) of the bullet start twisting in the riflings. While the back 1/2 is still being pushed/bumped up/enlarged in the ball throat of the chamber.
You want the size of the bullet to be the size of the ball throat. Too big and the bullet will get swaged down as it goes thru the ball throat being swaged to the size/dimension of the ball throat. As with anything under pressure, it will go to the least point of resistance. Too small and the same thing happens, side to side play movement and the bullet is bumped up to the ball throat's diameter.
You want a cast bullet that doesn't have a long pointy nose to it. When driven hard the nose will "slump" and accuracy will be destroyed. Bore riding nosed bullets can only be pushed so hard (pressure)/fast (rifling & twist). You will know real fast when you exceeded your bbl/bore riding nosed bullets stability/fit.
The lyman 311466 is a proven hv design.
lyman 311466 mold - Bing
A couple of guys got together and designed this bullet and neo makes the molds. They have gotten 3000+fps/2-moa with this bullet.
310-165-FN 30XCB, NOE Bullet Moulds
Myself I decided to use/test this lee bullet.
7.62 X 39 .312 Diameter 160 Grain 6 Cavity Mold CTL312-160-2R by Lee
As you can see all the bullets pictured above have a common theme. Namely, a short rounded/pointed nose (no nose slump) multiple shallow lube grooves, no wiper groove and they are not bore riding nose designs.
Wiper grooves are old/outdated. They were used back when lubes were well, iffy at best. Same goes for the large/deep lube grooves. Both of them are nothing more than a weak link in the body (chain) of the bullet.
I know you asked about 8mm bullets, I'm just putting out there what I've learned about cast/lead bullets when they are being used with high pressure/high velocity (jacketed bullet load data) loads.
If you don't use/choose a bullet with a strong body design that can take 40,000+psi and a nose design that can take 120,000+rpm. Then your just spitting in the wind.
No experience with commercial pc'd bullets. I have been experimenting with my own cast/coated bullets.
Home cast/home coated/home made gas checks
A link to alloys and the pressures they are used for.
Cast bullet reference on lead alloy's, min / max pressure, lube, shrinkage,
There are 2 main coating being used right now:
Commercial ='s hi-tech/polyurathane
Home ='s dry powdercoat powder/polyester
Bullet size/design:
Anything under pressure will go to the least point of resistance. Add to that the fact that your asking a lead bullet to be under pressure, have the front 1/2 (nose) of the bullet start twisting in the riflings. While the back 1/2 is still being pushed/bumped up/enlarged in the ball throat of the chamber.
You want the size of the bullet to be the size of the ball throat. Too big and the bullet will get swaged down as it goes thru the ball throat being swaged to the size/dimension of the ball throat. As with anything under pressure, it will go to the least point of resistance. Too small and the same thing happens, side to side play movement and the bullet is bumped up to the ball throat's diameter.
You want a cast bullet that doesn't have a long pointy nose to it. When driven hard the nose will "slump" and accuracy will be destroyed. Bore riding nosed bullets can only be pushed so hard (pressure)/fast (rifling & twist). You will know real fast when you exceeded your bbl/bore riding nosed bullets stability/fit.
The lyman 311466 is a proven hv design.
lyman 311466 mold - Bing
A couple of guys got together and designed this bullet and neo makes the molds. They have gotten 3000+fps/2-moa with this bullet.
310-165-FN 30XCB, NOE Bullet Moulds
Myself I decided to use/test this lee bullet.
7.62 X 39 .312 Diameter 160 Grain 6 Cavity Mold CTL312-160-2R by Lee
As you can see all the bullets pictured above have a common theme. Namely, a short rounded/pointed nose (no nose slump) multiple shallow lube grooves, no wiper groove and they are not bore riding nose designs.
Wiper grooves are old/outdated. They were used back when lubes were well, iffy at best. Same goes for the large/deep lube grooves. Both of them are nothing more than a weak link in the body (chain) of the bullet.
I know you asked about 8mm bullets, I'm just putting out there what I've learned about cast/lead bullets when they are being used with high pressure/high velocity (jacketed bullet load data) loads.
If you don't use/choose a bullet with a strong body design that can take 40,000+psi and a nose design that can take 120,000+rpm. Then your just spitting in the wind.
2700fps/2-moa with cast/coated bullets
On another website a group of casters got together and wanted to really push the cast bullet envelope. They bought custom bbl's, designed a bullet and designed a case that reminded me of the 30-40 krag. Their goal what to shoot cast bullets @ hv and hold 2-moa @ 100yds (10-shot groups).
While 2-moa doesn't sound like much. It was a huge step forward in cast bullet performance/design. That xcb bullet I posted a link to above was the labor of their efforts. They were doing 2-moa or less 10-shot/2900fps+ groups with that bullet in their slow twist bbl's with custom chambers.
They are shooting 2-moa out to 600yds with their setups.
I followed their progress of learning alloys, lubes, powders, etc. Custom is 1 thing & using a common caliber is another. I decided to do some casting/playing with the 308w which was designed for jacketed bullets. Not a lot of neck length to hold the lead bullet and the chambers of the 308w have an extremely generous neck dimension. They also have a wide verity of twist rates.
I had a old puma rifle laying around that had a 1 in 12 twist 308w chamber. It was pretty much shot out. I did some testing with different cast/coated bullets. Then I changed bbl's to a 20" bull bbl with a standard 308w chamber and a 1 in 10 twist. Did a bunch of testing with it and then opened the throat's taper/leade of that bbl's chamber and re-tested everything. Then I re-barreled it again, this time with a 1 in 11 twist that had a custom chamber cut in it (175snk's) and had a loose 301/308 bore with 4-grooves.
It was nothing to shot bugholes @ 50yds and 1 to 1 1/2" 10-shot groups @ 100yds with all of the bbl's listed above with several (10+) cast bullet designs and a bunch oif different powders. With all the bbl's listed above I hit a wall that ranged from 1600fps to 2200fps depending on the bullet/bbl/alloy/etc.
On another website a group of casters got together and wanted to really push the cast bullet envelope. They bought custom bbl's, designed a bullet and designed a case that reminded me of the 30-40 krag. Their goal what to shoot cast bullets @ hv and hold 2-moa @ 100yds (10-shot groups).
While 2-moa doesn't sound like much. It was a huge step forward in cast bullet performance/design. That xcb bullet I posted a link to above was the labor of their efforts. They were doing 2-moa or less 10-shot/2900fps+ groups with that bullet in their slow twist bbl's with custom chambers.
They are shooting 2-moa out to 600yds with their setups.
I followed their progress of learning alloys, lubes, powders, etc. Custom is 1 thing & using a common caliber is another. I decided to do some casting/playing with the 308w which was designed for jacketed bullets. Not a lot of neck length to hold the lead bullet and the chambers of the 308w have an extremely generous neck dimension. They also have a wide verity of twist rates.
I had a old puma rifle laying around that had a 1 in 12 twist 308w chamber. It was pretty much shot out. I did some testing with different cast/coated bullets. Then I changed bbl's to a 20" bull bbl with a standard 308w chamber and a 1 in 10 twist. Did a bunch of testing with it and then opened the throat's taper/leade of that bbl's chamber and re-tested everything. Then I re-barreled it again, this time with a 1 in 11 twist that had a custom chamber cut in it (175snk's) and had a loose 301/308 bore with 4-grooves.
It was nothing to shot bugholes @ 50yds and 1 to 1 1/2" 10-shot groups @ 100yds with all of the bbl's listed above with several (10+) cast bullet designs and a bunch oif different powders. With all the bbl's listed above I hit a wall that ranged from 1600fps to 2200fps depending on the bullet/bbl/alloy/etc.
All the testing/re-barreling was leading up to spending some $$$ on a bbl that would be good for both cast and jacketed bullets. I have +/- $1000 in 30cal molds and wanted to puish the envelope with them accuracy wise along with extreme velocity for a lead bullet.
I ended up buying a 1 in 14 twist 30" bbl that had a .340" match 308w chamber. I bought a lee 6-cavity 160gr tl 312 bullet mold and started casting. The goal was to do 2-moa with a 2500fps+ load before winter/snow set in.
I shot/tested/setup the rifle bedding part of the action at a time. Wasn't sure if I want'ed min/max chamber lengths so I tested 3 different lengths. And fully bed the receiver/bbl/bbl lug after a little testing.
Didn't take long to get 2-moa 10-shot groups that were over 2500fps.
Same bullet cast at the same time/same alloy/sizer/gas checks/etc. The only difference was the bullet was traditionally lubed. As you can see accuracy fell off quickly. These were shot the same day as the bullets pictured above.
With the traditional lube tests above I only used lbt blue in the small tl lube grooves. I had some of the bullets left from that batch of cast bullets. So I lubed them with the lbt blue and then put 2 coats of 45/45/10 tumble lube on them and re-tested.Both velocity and accuracy was even with the same bullets that were pc'd.
Coated bullets not only seal the bbl with high pressure loads. They protect the bbl. I've ran the same coated bullets pictured above up past 2900fps. Accuracy started falling off. The more extreme/violent the load's pressures are coupled with the fact that I was asking a lead bullet to withstand 149,000+ rpm's.
Heavier bullets held there own in the 2400 +/- range. These 180gr sp's (cramer sp/hp) take after the lyman 311334 bullet. The long nose slumps easily. I got 2400fps+ out of them simply because of a long 30" bbl with a slow twist and an extremely slow burning powder (rl19).
You're bbl's twist is the limiting factor of your tests with lead/coated bullets. Pressure from the hv loads that find any weak links in the bullet coupled with the torques/rotational forces of the rpm's that go with fast twist bbl's. Make it a balancing act at best with lead/coated bullet.
That's why it easy to find accuracy in the 1600fps to 2000fps range with lead coated bullets in rifles. Start getting over 2000fps it gets harder, 2600fps+ is a lot of testing with a fast twist bbl.
I ended up buying a 1 in 14 twist 30" bbl that had a .340" match 308w chamber. I bought a lee 6-cavity 160gr tl 312 bullet mold and started casting. The goal was to do 2-moa with a 2500fps+ load before winter/snow set in.
I shot/tested/setup the rifle bedding part of the action at a time. Wasn't sure if I want'ed min/max chamber lengths so I tested 3 different lengths. And fully bed the receiver/bbl/bbl lug after a little testing.
Didn't take long to get 2-moa 10-shot groups that were over 2500fps.
Same bullet cast at the same time/same alloy/sizer/gas checks/etc. The only difference was the bullet was traditionally lubed. As you can see accuracy fell off quickly. These were shot the same day as the bullets pictured above.
With the traditional lube tests above I only used lbt blue in the small tl lube grooves. I had some of the bullets left from that batch of cast bullets. So I lubed them with the lbt blue and then put 2 coats of 45/45/10 tumble lube on them and re-tested.Both velocity and accuracy was even with the same bullets that were pc'd.
Coated bullets not only seal the bbl with high pressure loads. They protect the bbl. I've ran the same coated bullets pictured above up past 2900fps. Accuracy started falling off. The more extreme/violent the load's pressures are coupled with the fact that I was asking a lead bullet to withstand 149,000+ rpm's.
Heavier bullets held there own in the 2400 +/- range. These 180gr sp's (cramer sp/hp) take after the lyman 311334 bullet. The long nose slumps easily. I got 2400fps+ out of them simply because of a long 30" bbl with a slow twist and an extremely slow burning powder (rl19).
You're bbl's twist is the limiting factor of your tests with lead/coated bullets. Pressure from the hv loads that find any weak links in the bullet coupled with the torques/rotational forces of the rpm's that go with fast twist bbl's. Make it a balancing act at best with lead/coated bullet.
That's why it easy to find accuracy in the 1600fps to 2000fps range with lead coated bullets in rifles. Start getting over 2000fps it gets harder, 2600fps+ is a lot of testing with a fast twist bbl.
Sorry for being long winded, you are getting into an area that few reloads have excelled at. One thing I was interested in with hv/high pressure 308w loads using coated bullets was the affect they would have on the bore.
They bbl I'm using is extremely smooth. Typically it takes 1 shot per 1" of bbl to coat/season a bbl with lube when the bbl's clean. A borescope picture of the clean bbl/leade of the chamber.
This is what the muzzle of that 30" bbl looked like after 15-shot with those barely lubed lee tl bullets.
This is what the bbl looked like after 30 rounds of the traditional lubed/2600+fps bullets went down the tube.
Same bbl/throat after 30-shots with the pc'd bullet from a clean bbl.
The middle of the bbl
That's with a polyester bullet coating and a polyester filler to get full case capacity/100 load density. I know coat the pc'd bullets with the tumble lube 45/45/10 and there's no more black streaks left in the bbl.
They bbl I'm using is extremely smooth. Typically it takes 1 shot per 1" of bbl to coat/season a bbl with lube when the bbl's clean. A borescope picture of the clean bbl/leade of the chamber.
This is what the muzzle of that 30" bbl looked like after 15-shot with those barely lubed lee tl bullets.
This is what the bbl looked like after 30 rounds of the traditional lubed/2600+fps bullets went down the tube.
Same bbl/throat after 30-shots with the pc'd bullet from a clean bbl.
The middle of the bbl
That's with a polyester bullet coating and a polyester filler to get full case capacity/100 load density. I know coat the pc'd bullets with the tumble lube 45/45/10 and there's no more black streaks left in the bbl.
Good luck with you're coated bullets.
Keep in mind you can also use everything you learn about hv cast/coated bullets and apply it to paper patched bullets.
Those old 8mm mausers eat pp bullets like potato chips.
Keep in mind you can also use everything you learn about hv cast/coated bullets and apply it to paper patched bullets.
Those old 8mm mausers eat pp bullets like potato chips.
