Well crap....

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dellet
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Re: Well crap....

Post by dellet » Tue Jun 02, 2020 5:22 pm

I generally shoot either 1/5 or 1/10 twists and have everything in between. 1.5-2 MOA is pretty normal/easy in the AR's out to 200 yards. Most is 1100 fps or less, but enough up to 1500 fps in the 1/5 to not worry about the twist rate or bullet length/weight.

Hard cast, powder coated, low pressure powders.
300 Blackout, not just for sub-sonics.

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rebel
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Re: Well crap....

Post by rebel » Wed Jun 03, 2020 8:00 am

MeGrunt wrote:
Mon Jun 01, 2020 6:47 pm
I'm not rich. I didn't know it was a prerequisite to being on this forum.

I'm a 100% P&T Veteran. I live on a fixed income. I have a certain amount of "play" money I can spend every month.

I'm sure there are people here that have spent more on a BCG than I have in my build.

It's an Anderson lower, with a Anderson LPK. The upper is a 7.5" BCA with a 1/8" twist.

The first cast bullet I've tried is the MP 311410 hollow point. I did ladder loads, every .3 grs with H110, MP 300, 11FS, CFE Black and Heavy Pistol.

I did the same for the same bullet in a solid.

Next bullet is a NOE 311-158 FN, here I did ladder loads, every .3 gr with Reloader 7, CFE Black, Accurate 1680, Socom, Blackout, IMR 4227, and Lil Gun.

Next bullet is a NOE 311-198 SP. Loads every .3 gr with IMR 4198, RL7, CFE Black, 1680, IMR 4227, Socom, and Blackout.

Next bullet is a MP 311-235 Loads every .3 gr with same powders as NOE 311-198.

Load data was taken from closest weight jacketed bullet I could find. I started .3 gr under jacketed starting load and went to the closest load to max, but no over max.

Alloy used was half lino half pure. All bullets were plain base, all were either powder coated or Hi-Tek. Bullets were sized to .310.

In the past two months I've tested close to 200 different loads.

None of them will group. Not a single one. I'm lucky if I can keep five rounds on a 12" target at 25 yards.

Speer 125 TNT and Hornady 147 FMJ both shoot quite well.

I'm not getting any leading in the barrel but the muzzle device shows lead deposits as does the tail of the bolt. The gas rings were welded closed with lead.

I know that the 300 Blackout isn't the most accurate cartridge, nor is a 7.5" barrel the most accurate. But when jacketed bullets are shooting into one ragged hole and cast are in a wide pattern there's something wrong.
Not rich either. I have never had a problem with Anderson stuff. Not a caster, but all that commented are. I'd check on what they are suggesting. Those lead deposits will lead you to your problem I believe. I feel your frustration, have a Savage 110 243 that almost ended up in the wood stove until I found the right load.
You can't beat the mountain, pilgrim. Mountains got its own way.

excess650
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Re: Well crap....

Post by excess650 » Fri Jun 05, 2020 12:55 pm

MeGrunt wrote:
Tue Jun 02, 2020 2:48 pm
Let's put it this way.

Has anyone successfully used cast bullets in the 125 gr to 150 gr range in an AR with a 1/8" twist.

If so how.

Cast bullet RPM is limited to around 140,000 rpm. Above that you start to have problems.

With a 1/8" twist that would limit you to a velocity of around 1550 fps.

At this point if I want to use these lighter bullets I think my only option is a custom barrel with a 1/12" twist.
That theory you quote is pure BS. The author is so full of himself that he has brown eyes and bad breath.

My normal 300BO load is the Lee 155 w/GC sized .311" over enough H110 to average 1920fps across the chrono. As of late I'm loading some 140gr GC w/PC over compressed loads of 4227 that should be doing 2000-2100fps from the 16" 1-8" twist barrel. Accuracy of both is 1-1.5moa. I'm also shooting GC w/PC 59gr from a 16" 9" twist 556 in excess of 2700fps and accuracy on par with factory 55gr. Calculate that out and it'll spin Mister Twister's world off its axis. :lol:
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Jailer
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Re: Well crap....

Post by Jailer » Fri Jun 05, 2020 2:40 pm

MeGrunt wrote:
Tue Jun 02, 2020 2:48 pm
Let's put it this way.

Has anyone successfully used cast bullets in the 125 gr to 150 gr range in an AR with a 1/8" twist.

If so how.

Cast bullet RPM is limited to around 140,000 rpm. Above that you start to have problems.

With a 1/8" twist that would limit you to a velocity of around 1550 fps.

At this point if I want to use these lighter bullets I think my only option is a custom barrel with a 1/12" twist.
Lee 312-155-2R wheel weights for alloy sized to .310 over 15.3gr H110. Best shooting bullet I've tried so far. You're not going to get decent accuracy trying to push a plain base bullet to those velocities in an AR platform. Don't own the AR any longer but they shot great in a DDm4v5 I owned for a bit until someone decided they needed it a lot more than I did.

And yeah, give up on the whole "RPM therory" as the previous poster said, it's utter nonsense. Don't let someone ever tell you what you can't do.

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dellet
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Re: Well crap....

Post by dellet » Fri Jun 05, 2020 3:04 pm

I pushed these bullets to the max to see what they could do. Velocity and pressures noted. 15-1600 fps in a 7'", 1/5 twist AR was minute of clays at 100 yards.

Image

If you look at this bullet carefully you can see the straight groove of the land, before it starts to twist the bullet. Too high of start pressure and speed for the hardness of the bullet. Completely stripped the coating.

Image

Personally I think the op's problem is the barrel, but I wouldn't rule out the bullet powder combination.
300 Blackout, not just for sub-sonics.

MeGrunt
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Re: Well crap....

Post by MeGrunt » Fri Jun 05, 2020 3:38 pm

I'm headed to the range tomorrow with a bunch of heavy loads to try. I also picked up some of the 150 gr Berry's .30-30 bullets to try.

excess650
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Re: Well crap....

Post by excess650 » Fri Jun 05, 2020 5:10 pm

If you're going to switch from jacketed to cast, be sure to get the copper out of the bore. Your leaded gas rings are the result of gas cutting the bases of your bullets as they pass over the gas port. The base of the bullet is the steering end, so when it exits the muzzle, high pressure flows through the gas cut and puts the bullet off POA. Use GCs, quench your bullets and allow them to age at least a week before you shoot them.
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MeGrunt
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Re: Well crap....

Post by MeGrunt » Sat Jun 06, 2020 5:54 pm

excess650 wrote:
Fri Jun 05, 2020 5:10 pm
If you're going to switch from jacketed to cast, be sure to get the copper out of the bore. Your leaded gas rings are the result of gas cutting the bases of your bullets as they pass over the gas port. The base of the bullet is the steering end, so when it exits the muzzle, high pressure flows through the gas cut and puts the bullet off POA. Use GCs, quench your bullets and allow them to age at least a week before you shoot them.
The bullets were over a month old.

Today's range trip was almost a complete bust. 30 total loads with three heavy bullets. NOE 311-198 SP, MP 311-235, Lee 230.

The best I could do with the cast was a load with the NOE. I had two shots 4" left of the center that were touching, two shots 5" to the right of the center that were touching and one in the center.

I had picked up some of the Berry's .30-30 bullets after reading about them here. Those shot very well. At 25 yards with a red dot I was cutting one ragged hole with five shot groups. I had five loads to try with this bullet and the minimum charge of H110 was the most accurate.

There was no leading of the bolt. Bore was sparkling. This barrel seems to hate cast bullets. I have some gas checks coming to try on my one mold that will take a gas check, the NOE 198. I'll see of that makes a difference.

I shot three other rifles today. One was a 7.62x39 AR that I assembled. Other than the really crappy trigger this carbine shot very well. I just had some Wolf steel case on hand an it was cutting one ragged hole with five shot groups.

Next was a .223 Wylde upper. With some cheap blasting ammo it shot very well.

Last was my PSA 10" 9mm pistol. 33 rounds in under 1.5" at 25 yards.

We cut the trip short as it was a bit warm here in North Texas today.

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Re: Well crap....

Post by MeGrunt » Sun Sep 20, 2020 4:07 pm

I picked up a 10.5" Bear Creek 300 BO barrel and built a new upper.

My plain based cast bullets are shooting quite well in it. They also shoot quite well in my RAR bolt gun. I guess that 7.5" barrel just didn't like cast bullets.

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