How fast can you push 36 gr. Varmint Grenades in a 1-9 twist .223? - Page 2

McClintock · June 16, 2009, 12:05 PM

Kendo,

Haven't noticed any copper fouling, but then I'm not pushing them very fast, either. One poster said he had them up to 4600 fps

in a 220 Swift, and no issues.

Oklahoma sounds like fun, though no immediate plans to be in your area. Same here, you're ever in southern Saskatchewan, give me a shout, and we'll go shoot stuff.

Cheers!
McClintock

**Unclenick** · June 16, 2009, 03:45 PM

From the technical end, if you have Excel or Calc (free Open Office Suite's spreadsheet) you can download the free bullet stability and twist estimator file from my file repository at drop.io/unclenick. Bullet stability depends on both bullet length and weight. The spread sheet estimates that at 3600 fps about a 10.5" twist would be close to ideal, giving Harold Vaughn's favorite gyroscopic stability factor of s = 1.4. 9" give 1.90, which isn't that far above, and a little too high is better than a little too low, since the bullet becomes unstable below s = 1, which it gives as a 12.5" twist for marginal stability. Anything slower is likely to have it hitting the paper sideways and off-center.

McClintock,

I wanted to suggest that Varget is a bit slow for best ballistic efficiency and uniform powder burning with that light bullet. Not enough inertial resistance to acceleration. QuickLOAD predicted your 26 grain load packed into a tight case (don't know what case you used, but this was 28.8 grains of water capacity, like some military cases) would produce 3278 fps, which is pretty close to your middle range for that load. Because that is in agreement, I expect the predicted peak pressure is as well, which was only 39,220 psi. B.E. was 15.3%. Reloader 10X or either IMR or H 4198 should do well with that light bullet and get you to 50Kpsi to 55 kpsi and to higher velocities and get closer to 25% B.E. Even IMR and H 4227 holds some promise here. Predicted velocities above 3,700 fps seem to be possible with them.

Kendo · June 16, 2009, 05:30 PM

Thanks McClintock.

McClintock · June 16, 2009, 10:10 PM

Thanks, UncleNick for the detailed info. Looks like I have A LOT more experimenting to do with this 223 load. I will definitely grab that spreadsheet, looks interesting.

The cases I was using were American Eagle brass, which I purchased, fired, and then loaded. 26.0 grains was about all they would hold without compressing the load, which I wanted to avoid. I chose Varget for my first kick of the cat at rifle reloading, because it seemed to be a good all-around powder, according to what I've read on this forum. You guys at TFL never disappoint, I've learned so much from everyone here.

Cheers!
McClintock

Kato_Guy · June 17, 2009, 10:34 PM

I have been screwing around with these grenades for a little while I have settled on 26.0 of benchmark that is just under 3500fps. If I remember corectly they are seated to 2.200" oal.

I had talked to a rep from barnes a while back and they said that they tested these bullets out of an 8" twist barrell. Mine is a 9" and seems to be working great. It is a copper tin bullet so its bigger than your average lead bullet!

Good luck it took me a little more work with these than any other bullet!

kyle

Subgauge · December 17, 2009, 09:55 PM

I was calling around today to try to find some of the 36 gr. VG's, but no luck. Turns out I had almost 500 on my shelf. Loaded up some with 26 gr of Varget for my .223 Kimber Longmaster which has a 1/12 bbl. Seems I shot some in the past, but was thinking it was just another bullet. Going to pick up a CZ in .223 on NYE, as my dealer sells all his guns at cost, so he doesn't have to pay tax on them. Eager to see how they will print and maybe shoot a crow or two in some recently gathered corn fields.
Subgauge

June 16, 2009, 12:05 PM	#26
McClintock Senior Member Join Date: December 5, 2008 Location: The Bald Prairie of Southern Saskatchewan, Canada Posts: 305	No copper fouling Kendo, Haven't noticed any copper fouling, but then I'm not pushing them very fast, either. One poster said he had them up to 4600 fps in a 220 Swift, and no issues. Oklahoma sounds like fun, though no immediate plans to be in your area. Same here, you're ever in southern Saskatchewan, give me a shout, and we'll go shoot stuff. Cheers! McClintock

June 16, 2009, 03:45 PM	#27
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	From the technical end, if you have Excel or Calc (free Open Office Suite's spreadsheet) you can download the free bullet stability and twist estimator file from my file repository at drop.io/unclenick. Bullet stability depends on both bullet length and weight. The spread sheet estimates that at 3600 fps about a 10.5" twist would be close to ideal, giving Harold Vaughn's favorite gyroscopic stability factor of s = 1.4. 9" give 1.90, which isn't that far above, and a little too high is better than a little too low, since the bullet becomes unstable below s = 1, which it gives as a 12.5" twist for marginal stability. Anything slower is likely to have it hitting the paper sideways and off-center. McClintock, I wanted to suggest that Varget is a bit slow for best ballistic efficiency and uniform powder burning with that light bullet. Not enough inertial resistance to acceleration. QuickLOAD predicted your 26 grain load packed into a tight case (don't know what case you used, but this was 28.8 grains of water capacity, like some military cases) would produce 3278 fps, which is pretty close to your middle range for that load. Because that is in agreement, I expect the predicted peak pressure is as well, which was only 39,220 psi. B.E. was 15.3%. Reloader 10X or either IMR or H 4198 should do well with that light bullet and get you to 50Kpsi to 55 kpsi and to higher velocities and get closer to 25% B.E. Even IMR and H 4227 holds some promise here. Predicted velocities above 3,700 fps seem to be possible with them. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

June 16, 2009, 10:10 PM	#29
McClintock Senior Member Join Date: December 5, 2008 Location: The Bald Prairie of Southern Saskatchewan, Canada Posts: 305	Thanks UncleNick Thanks, UncleNick for the detailed info. Looks like I have A LOT more experimenting to do with this 223 load. I will definitely grab that spreadsheet, looks interesting. The cases I was using were American Eagle brass, which I purchased, fired, and then loaded. 26.0 grains was about all they would hold without compressing the load, which I wanted to avoid. I chose Varget for my first kick of the cat at rifle reloading, because it seemed to be a good all-around powder, according to what I've read on this forum. You guys at TFL never disappoint, I've learned so much from everyone here. Cheers! McClintock

December 17, 2009, 09:55 PM	#31
Subgauge Junior Member Join Date: December 17, 2009 Posts: 1	N GA I was calling around today to try to find some of the 36 gr. VG's, but no luck. Turns out I had almost 500 on my shelf. Loaded up some with 26 gr of Varget for my .223 Kimber Longmaster which has a 1/12 bbl. Seems I shot some in the past, but was thinking it was just another bullet. Going to pick up a CZ in .223 on NYE, as my dealer sells all his guns at cost, so he doesn't have to pay tax on them. Eager to see how they will print and maybe shoot a crow or two in some recently gathered corn fields. Subgauge

June 16, 2009, 05:30 PM	#28
Kendo Senior Member Join Date: March 20, 2009 Location: Oklahoma Posts: 103	Thanks McClintock.

June 17, 2009, 10:34 PM	#30
Kato_Guy Senior Member Join Date: March 26, 2006 Location: Minnesota Posts: 212	I have been screwing around with these grenades for a little while I have settled on 26.0 of benchmark that is just under 3500fps. If I remember corectly they are seated to 2.200" oal. I had talked to a rep from barnes a while back and they said that they tested these bullets out of an 8" twist barrell. Mine is a 9" and seems to be working great. It is a copper tin bullet so its bigger than your average lead bullet! Good luck it took me a little more work with these than any other bullet! kyle