GRT NextGen

[jelenko]

For a powder to be in GRT, someone needs to do enough testing to gather the data for the powder 'model'. Simply means no one has done it.

 

[SeabeeKen]

Does anybody know why H380 isn't in the system? Or if the name has changed. I have a pound of it I would like to run. My manuals say it's good for 7mm08, 260, 243, 22-250, etc. But I can't find it in GRT.

I was working on the initial powder model development for H-380 when Gordon passed. I couldn't submit anything more to GRT Lab after he passed. I did manage to get LT30 and 32 development model 1 in before he passed but it hasn't moved further since he passed

 

[StumpGrinder]

I was working on the initial powder model development for H-380 when Gordon passed. I couldn't submit anything more to GRT Lab after he passed. I did manage to get LT30 and 32 development model 1 in before he passed but it hasn't moved further since he passed

I understand, thanks for your response. As far as I understand there is no other powder close enough to use as an equivalent. Is that correct?

 

[SeabeeKen]

I understand, thanks for your response. As far as I understand there is no other powder close enough to use as an equivalent. Is that correct?

Leverevolution powder is close to it on a burn chart but the powder is different shape, volume, and density. If you have a way to measure these things and a pressuretrace 2 system to measure pressure, then I would attempt it. The first step would be to do a 2x2x2x5 test and submit it to Charlie on the discord for pressure testing (he has a PT2). Attached a worksheet for the 2x2x2x5 if you're interested as a guide. Charlie also recommends running a ladder test to find pressure. Its quite a process and consumes a good amount of components to do this. I'd check with Charlie on the discord to be sure he is still willing to do his tests. There are also a number of posts over there on methods to do the volume measurements etc
IF GRT labs ever opens back up, I'll do more powder tests. I dont know if any of this helps but it should point you in the right direction

 

[StumpGrinder]

Leverevolution powder is close to it on a burn chart but the powder is different shape, volume, and density. If you have a way to measure these things and a pressuretrace 2 system to measure pressure, then I would attempt it. The first step would be to do a 2x2x2x5 test and submit it to Charlie on the discord for pressure testing (he has a PT2). Attached a worksheet for the 2x2x2x5 if you're interested as a guide. Charlie also recommends running a ladder test to find pressure. Its quite a process and consumes a good amount of components to do this. I'd check with Charlie on the discord to be sure he is still willing to do his tests. There are also a number of posts over there on methods to do the volume measurements etc
IF GRT labs ever opens back up, I'll do more powder tests. I dont know if any of this helps but it should point you in the right direction

That's way above my pay grade! I really like Leverevolution, it gives the top combination of case fill and burn in many of the cartridges I load for. I will do a ladder test on H380.

 

[StumpGrinder]

That's way above my pay grade! I really like Leverevolution, it gives the top combination of case fill and burn in many of the cartridges I load for. I will do a ladder test on H380.

Leverevolution powder is close to it on a burn chart but the powder is different shape, volume, and density. If you have a way to measure these things and a pressuretrace 2 system to measure pressure, then I would attempt it. The first step would be to do a 2x2x2x5 test and submit it to Charlie on the discord for pressure testing (he has a PT2). Attached a worksheet for the 2x2x2x5 if you're interested as a guide. Charlie also recommends running a ladder test to find pressure. Its quite a process and consumes a good amount of components to do this. I'd check with Charlie on the discord to be sure he is still willing to do his tests. There are also a number of posts over there on methods to do the volume measurements etc
IF GRT labs ever opens back up, I'll do more powder tests. I dont know if any of this helps but it should point you in the right direction

In the Hodgdon 2025 Annual Manual H380 is sandwiched between Leverevolution on top and Rsmshot Big Game below in the burn rate chart. I ran simulations with these two on GRT and they look promising for 243 Winchester with 85 grain Barnes ttsx. I have an AR 10 in 243 Winchester with a 1:8 barrel. When I get some of these I'll do a ladder test with my Labradar and post the results here. I have some 80 grain ttsx but I use them in my 6x45. The H380 also has application for 260 and 7mm08 which I have so I'm sure I can find a place to use it. I have quite a few 7mm bullets so I may start there.

 

[StumpGrinder]

Leverevolution powder is close to it on a burn chart but the powder is different shape, volume, and density. If you have a way to measure these things and a pressuretrace 2 system to measure pressure, then I would attempt it. The first step would be to do a 2x2x2x5 test and submit it to Charlie on the discord for pressure testing (he has a PT2). Attached a worksheet for the 2x2x2x5 if you're interested as a guide. Charlie also recommends running a ladder test to find pressure. Its quite a process and consumes a good amount of components to do this. I'd check with Charlie on the discord to be sure he is still willing to do his tests. There are also a number of posts over there on methods to do the volume measurements etc
IF GRT labs ever opens back up, I'll do more powder tests. I dont know if any of this helps but it should point you in the right direction

Ok so this is my ladder test with Hodgdon H380 in 7mm08. I used BR 2 primers, 139 grain flat base soft point bullets. They are factory seconds from Midway USA so I don't know what brand. I was using mostly Winchester brass but I accidentally got 2 federal cases in the mix and they were the only 2 that showed any pressure signs. They both had slight ejector marks but no other signs. Velocity was with Labradar as follows.
1. Winchester case, 46 grains, 2762 fps
2. Winchester case, 46.3 gr, 2802 fps
3. Federal case, 46.6 grains, 2811
4. Winchester case, 46.9 gr, 2819
☆5. Federal case, 47.2 gr, 2896☆
6. Winchester case, 47.5 gr, 2842

The Modern Reloading Manual 2nd edition from Lee lists 47 grains of H380 as the maximum charge with a Muzzle Velocity of 2807 fps and a pressure of 54,900. Which I thought was pretty low for a Rugger American so I went a little above that. I only have a 50 yard range so not really a good accuracy test but the best groups were 3 holes touching at 47.2 and 47.5.

I reload mixed brass and because I had a slight ejector at 46.6 grains, I dropped back to 46.3 and loaded 30 rounds for deer hunting. I know that In cooler weather they would have been fine even in the Federal cases however for the distances I shoot 2800 fps will be just fine.