Could use some help/advice on which bullet to use on the load chart, and...

[eastman]

It seems with pistol you all are more concerned about exceeding a speed if I'm reading things correctly.

You did read us wrong. The vast majority of shooters here care a lot more about accuracy.

And the one thing we've learned is that accuracy never happens at Max Load. It's usually in the 93 to 95% of Max Load range.

I interpreted his comment differently than you did.

I read "concerned about exceeding a speed" as meaning an upper velocity limit to make certain you are not over the pressure specification, since there are no obvious pressure indicators.

[ropedrag]

@ eastman, for the win

Yes 100% related to concerns of over-pressurization

[Wobbly]

It seems with pistol you all are more concerned about exceeding a speed if I'm reading things correctly.

You did read us wrong. The vast majority of shooters here care a lot more about accuracy.

And the one thing we've learned is that accuracy never happens at Max Load. It's usually in the 93 to 95% of Max Load range.

I interpreted his comment differently than you did.

I read "concerned about exceeding a speed" as meaning an upper velocity limit to make certain you are not over the pressure specification, since there are no obvious pressure indicators.

Oh, I get all that. But velocity is a Limit, and not a Goal. We're not out searching for the Limit. We are certainly aware of the Limit and mindful of it, but our concern, our quest is Accuracy.

And I don't think you'll ever get anything over 1080fps out of N320, even with a long barrel. You'll need N330 or N340. I think the data was already collected in a 16" test barrel, and so you won't be getting a free ride over 1100fps. The entire thing about N320 in a pistol is that at Minor PF you're shooting the loads at 98 or 99% of Max Load and thus wringing every ounce of efficiency out of the load. At the highest levels of pistol competition, that's a good thing.


No matter which it is, I believe you have lost sight of the Load Limits if you are truly considering testing 4.2 and 4.3gr of N320 with a 124gr bullet. How dangerous that might be I do not know. N320, being single-based, is rather benign.

All the best.

[ropedrag]

No matter which it is, I believe you have lost sight of the Load Limits if you are truly considering testing 4.2 and 4.3gr of N320 with a 124gr bullet. How dangerous that might be I do not know. N320, being single-based, is rather benign.

All the best.

Which brings us back to one of my original questions and the title of this thread. I've two 124 gr bullets, both from RMR, one a FMJ (brass) RN and the other a FMJ tunicated cone. When your specific bullet make/model isn't listed what is the approach?

In this case there are several 124gr bullets referenced in the official VV load data, 3 of which are the the same COL as I'm using, of these two are listing max load of 4.3 and one is 4.0. I chose the 4.0 as max for no other reason than it was the safest choice.

I'm intending on taking this 124gr FMJ RN to 4.3 by way of 4.1, .2 , 3 while watching speed as my benchmark for over pressurization. The only reason I'm doing this is because the charge weights I've tested (3.4 through 4.0 in .01 steps) are inaccurate rounds on target. I'm 100% chasing accuracy and would just as well not have to run up to max to find it but with this bullet, powder, gun combination it appears I may have to.

Watching my speeds means that I'm using the speeds of the max charge weights listed by VV for the 3 with the same COL which are 1066, 1070, 1096. Staying on the low side I'm using 1070, which as stated on their chart is for a 4" barrel.

Using Ballistics buy the inch as a resource it appears there is a delta of about 180fps between a 4" and 16" barrel with 9mm 124gr rounds. So 1070 + 180 = 1250 this is a *calculated* max speed

In the ladder I've loaded and shot thus far (3.4 to 4.0) the typical fps jump per .01 increase of charge weight was 25+/-. Again I was running 5 round steps so it's solid data. Anyway my maximum load thus far, at 4.0 yielded 1109 fps. If the fps steps remain somewhat consistent at 25 fps per .1 and I'm going up .3 it would equal a 75 fps increase over the established 1109 or... 1181. At 1181 this would seem to be in the safe zone in relationship to the 1250 *calculated* max. I'd likely pull the plug a bit over 1200 anyway if it goes that high.

@ wobbly, if you tell me my logic on this is bad or sketchy I will 100% respect that. I'm totally willing to accept that this powder, bullet, gun combo might be a dud, I'm only trying to learn as I go.

[painter]

4.3 gr is over max load for a 124 gr RN/FMJ. Why are you doing that?

[Wobbly]

Which brings us back to one of my original questions and the title of this thread. I've two 124 gr bullets, both from RMR, one a FMJ (brass) RN and the other a FMJ truncated cone. When your specific bullet make/model isn't listed what is the approach?

Comparable bullets are selected by sheath material and weight. In your case any 124gr jacketed bullet.

In this case there are several 124gr bullets referenced in the official VV load data, 3 of which are the the same COL as I'm using, of these two are listing max load of 4.3 and one is 4.0. I chose the 4.0 as max for no other reason than it was the safest choice.

They don't need to be the same OAL, but it helps. The real criteria is bullet seating depth (actually volume inside the case and under the bullet), which is determined by OAL and bullet length... not merely OAL by itself. This is why we keep a list of bullet lengths.

After all that, beginning at the Starting Load takes out all the other variables.

I'm intending on taking this 124gr FMJ RN to 4.3 by way of 4.1, 4.2 , 4.3gr while watching speed as my benchmark for over pressurization. The only reason I'm doing this is because the charge weights I've tested (3.4 through 4.0 in .01 steps) are inaccurate rounds on target. I'm 100% chasing accuracy and would just as well not have to run up to max to find it but with this bullet, powder, gun combination it appears I may have to.

OK, good. Then I did misunderstand. My apologies. But I don't think there's going to be anything there. Try your next slower powder or N330.

Watching my speeds means that I'm using the speeds of the max charge weights listed by VV for the 3 with the same COL which are 1066, 1070, 1096. Staying on the low side I'm using 1070, which as stated on their chart is for a 4" barrel.

I totally agree with that. Which is why I don't think you'll see any higher speeds.

I only shoot 4" barrels, so I've never looked for listed barrel lengths in the VV manual. I assumed 16" test barrels.

Using Ballistics buy the inch as a resource it appears there is a delta of about 180fps between a 4" and 16" barrel with 9mm 124gr rounds. So 1070 + 180 = 1250 this is a *calculated* max speed.

OK I believe you. But I have no experience in this area.

In the ladder I've loaded and shot thus far (3.4 to 4.0) the typical fps jump per .01 increase of charge weight was 25+/-. Again I was running 5 round steps so it's solid data. Anyway my maximum load thus far, at 4.0 yielded 1109 fps. If the fps steps remain somewhat consistent at 25 fps per 0.1 and I'm going up 0.3gr it would equal a 75 fps increase over the established 1109 or... 1181. At 1181 this would seem to be in the safe zone in relationship to the 1250 *calculated* max. I'd likely pull the plug a bit over 1200 anyway if it goes that high.

0.1gr not .01

You are assuming a simple straight line growth with your 75fps, and it is not. You are also assuming that Velocity and Pressure always advance 1:1, which doesn't always happen at the high end of the load. You need to become super aware of other signs of pressure, and watch for Velocity becoming asymptotic rather than continuing to climb as expected. This cartoon tries to explain...



The 1:1 relationship is true within the (green) safe loading zone. But Velocity seems to fall off above that, while Chamber Pressure zooms upward, faster and faster. You can really get in trouble fast chasing that "calculated" 10fps bullet velocity that never quite materializes.

And this pitfall typically happens sooner with "faster powders". However, I suspect that's usually with fast double-base powders due to the unstable nature of nitroglycerin content. I have no idea if you are safer because N320 is single-base. I'm not a chemist or a ballistics expert. This is knowledge that I have pieced together. So I have no way to guide you.

@ wobbly, if you tell me my logic on this is bad or sketchy I will 100% respect that. I'm totally willing to accept that this powder, bullet, gun combo might be a dud, I'm only trying to learn as I go.

That's where we all are, my friend. You simply have a material combination that falls outside my area of study.

 

[ropedrag]

In this case there are several 124gr bullets referenced in the official VV load data, 3 of which are the the same COL as I'm using, of these two are listing max load of 4.3 and one is 4.0. I chose the 4.0 as max for no other reason than it was the safest choice.

They don't need to be the same OAL, but it helps. The real criteria is bullet seating depth (actually volume inside the case and under the bullet), which is determined by OAL and bullet length... not merely OAL by itself. This is why we keep a list of bullet lengths.

After all that, beginning at the Starting Load takes out all the other variables.

Thanks Wobbly, Yeah I guess that's an obvious answer... I had thought about it but then overlooked factoring it in. They don't make it easy on us because none of the bullet manufactories list their bullet lengths, the ones I've looked at anyway. But for building pressure in the casing it would be the variable, it's either further in or further out if the COL is the same.

Interesting that the RMR 124 FMJ RN bullet length has a crazy range. I measured 20 and they are very inconstant with a total range of .017 which seems like a lot, and the average being .6050. The RMR FMJ turncated FP match winners however were great at .5540 with a range of .001, maybe that's why we hear good things about them.....

After giving more thought to working the edges with the VV N320 in this situation I'm not going to pursue it. I'd never want to put that load in the Shadow 2 even if it worked out for the scorpion. Besides the Allient Sport Pistol at 4.4 (within published charge weight range) yielded good accuracy and decent ES and SD so I'm going to run with that for the scorpion. Maybe it was simple wishful thinking as opposed to being totally naive that with 2 powders and 2 bullets that I could cook up 4 loads that would perform well in both the scorpion and Shadow 2. Learning all the time!

[George16]

Interesting that the RMR 124 FMJ RN bullet length has a crazy range. I measured 20 and they are very inconstant with a total range of .017 which seems like a lot, and the average being .6050. The RMR FMJ turncated FP match winners however were great at .5540 with a range of .001, maybe that's why we hear good things about them.....

After giving more thought to working the edges with the VV N320 in this situation I'm not going to pursue it. I'd never want to put that load in the Shadow 2 even if it worked out for the scorpion. Besides the Allient Sport Pistol at 4.4 (within published charge weight range) yielded good accuracy and decent ES and SD so I'm going to run with that for the scorpion. Maybe it was simple wishful thinking as opposed to being totally naive that with 2 powders and 2 bullets that I could cook up 4 loads that would perform well in both the scorpion and Shadow 2. Learning all the time!

I’m really glad you’re not going to pursue your plan of loading at 4.2 or 4.3 Gr. There’s no need for it especially for a fast powder like N320 imo. Besides, higher velocity doesn’t normally result in better accuracy. By the way, are you reloading for competition or just range plinking?

The match winners are great bullets. I have done load development for my shadow and MPX (8” and 16” barrels) using the same load recipe; 4.0 grains of Sport Pistol @ 1.120-1.125 OAL. Average velocity was 1045 for 129.50 PF with the shadow 2, 1072 FPS @ 132 PF for the 8” MPX and 1125 FPS @ 139.5 PF for the 16” MPX.

Accuracy on the shadow 2 was less than 3” at 25 yards shooting with both hands while standing. It was more accurate on the MPX at less than 2” at 25 yards shooting while standing.

These are the loads I shoot in competition for my shadow 2. I don’t use it for the MPX so it won’t lead up the compensator. However, I load the same data for Precision Delta’s 124 Gr JHP for them which I also use in competition. Accuracy is a little bit better compared to the match winners.

[Wobbly]

Yeah I guess [changes in bullet depthis] an obvious answer... I had thought about it, but then overlooked factoring it in. They don't make it easy on us because none of the bullet manufactures list their bullet lengths, the ones I've looked at anyway. But for building pressure in the casing it would be the variable, it's either further in or further out if the COL is the same.

• For same weight bullets, JHP are typically longer than FMJ's because of the hollowed out center. The missing weight shows is added on as extra bullet length.

• You need to spend more time in our Directory. There are a lot of resources there, including common Bullet Lengths.