n2ipsc Posted July 8, 2013 Share Posted July 8, 2013 Well, here's a new experience... Working up loads (well, trying to, anyway...keep reading) with Longshot for my Limcat (full-length, V-6 ported, 4-chamber comp). 124g MT Gold JHPs, once-fired Federal cases, WSR primers, 1.165" OAL, Oehler 35P chrono. Everything progressing nicely... 7.0 gr Longshot - 1311fps/34fps SD/162PF 7.2 gr Longshot - 1324fps/28fps SD/164PF 7.4 gr Longshot - 1348fps/18fps SD/167PF So far, so good; velocities increasing reasonably linearly, std dev's tightening, seemingly closing in on good load, would like a little cushion on PF, so, a little bit more should get me there... 7.6 gr Longshot - 1298fps/49fps SD (!) 7.8 gr Longshot - 1299fps/35fps SD (!!) Chrono'd regular load (7.8 Silhouette) as check - spot on @1378 fps... Hmmmm... Back to the bench, calibrate scales (yes, two, as cross-check), load two more test batches @ 7.6 & 7.8, weighing each charge...and... 7.6 gr Longshot - 1299fps/57fps SD (!) 7.8 gr Longshot - 1307fps/35fps SD (!!) Chrono'd regular load (7.8 Silhouette) again as check - spot on @1380 fps... So, if this (counter-intuitive!) data is to be believed, one would have to be well north of 8gr with Longshot to make, oh, say, 170pf in my particular gun, but am guessing, and I think correctly, that at some point not very far above 7.8 things are going to spike dramatically. 7.4gr load too close to 165 for comfort. My search-foo may be lacking, but I can find nothing anywhere noting this phenomena (more powder = LOWER velocities?!) with Longshot in Major 9. Has anyone else experienced this issue? "Recovering" velocities by going higher yet on charge weight? Keen to hear any feedback... Link to comment Share on other sites More sharing options...
gng4life Posted July 8, 2013 Share Posted July 8, 2013 Yes, it's actually common with some powders. You've reached the apex for that powder and reached the point of diminishing returns. I have experienced it and I have read lots of shooters on here with the same situation. The only option is usually to play with the OAL while watching pressure or go to a different powder/bullet/primer. Link to comment Share on other sites More sharing options...
MoNsTeR Posted July 8, 2013 Share Posted July 8, 2013 I experienced something similar with Power Pistol. Some powders reach a point where additional powder mass doesn't burn, it just gets ejected out the bore. I suspect that even if you crammed 9 grains in there velocity would not go up. Link to comment Share on other sites More sharing options...
razorfish Posted July 8, 2013 Share Posted July 8, 2013 (edited) So close... I would polish up the powder measure and try 7.5gn before reducing the OAL. Maybe that's the true apex. Good luck. Edited July 8, 2013 by razorfish Link to comment Share on other sites More sharing options...
pskys2 Posted July 8, 2013 Share Posted July 8, 2013 (edited) Also a big danger sign as pressures will start spiking, with no gain in veloctiy. Back off! Don't go any further. You can try going a bit longer on your OAL with the last powder charge and you will probably see a velocity increase. I know that is counter intuitive, but I've seen it many times. But with 9 major, doubt if you can go much. And you don't want to reduce the OAL, unless you reduce the charge and even then it probably won't help any. Edited July 8, 2013 by pskys2 Link to comment Share on other sites More sharing options...
n2ipsc Posted July 8, 2013 Author Share Posted July 8, 2013 Thanks all. Have seen velocities plateau in the past, with increasing pressure signs - but seeing a DIP in velocities is a first (for me, anyway)... Back to the laboratory Link to comment Share on other sites More sharing options...
superdude Posted July 8, 2013 Share Posted July 8, 2013 (edited) I've seen the same thing with Longshot in 10mm with several different bullet weights. At some point you hit a wall, and presumably the pressures can get scary. The 10mm loads showed no pressure signs in my Witness, but blew the primers out of the case in a Clark 1911 barrel! Yikes. Edited July 8, 2013 by superdude Link to comment Share on other sites More sharing options...
deerassassin22 Posted July 14, 2013 Share Posted July 14, 2013 I also had this problem using Ramshot Competition I though it was just me having a brain fart happened with 9mm and 40cal. Thanks for confirming I'm not crazy. Link to comment Share on other sites More sharing options...
Poppa Bear Posted July 14, 2013 Share Posted July 14, 2013 Add a couple of inches to your barrel and you will see it climb again. You have reached a point where the excess powder is not getting burnt until it exits the barrel. Longshot is slow enough to give this problem. Link to comment Share on other sites More sharing options...
GrumpyOne Posted July 14, 2013 Share Posted July 14, 2013 Add a couple of inches to your barrel and you will see it climb again. You have reached a point where the excess powder is not getting burnt until it exits the barrel. Longshot is slow enough to give this problem.This is the correct answer. Link to comment Share on other sites More sharing options...
CocoBolo Posted July 14, 2013 Share Posted July 14, 2013 (edited) No I idea why you would be dinking around with Loud shot if you have Silhouette. But yes I have had them slow down when adding powder, followed closely by primer flow. I had an old worn out barrel that I had to keep whicking up the charge to get to pf, one day I just gave up and got a new barrel. I've taken Silhouette to 189pf in 9 major, without any issues, and that is just 8.3gr w/124 on a cool day, don't try this at home kids. My 7.7gr load with a dawson dp2 in a true 5" (cone) makes 172pf on a hot day, another 1/2" and going from Clark to Schueman barrel 5.4 the velocity drops 20 fps, go figure. Try a structured expierement with 3N38, I need a reason to try it. If your looking to take a road not often taken use 10gr of AA#7 with a 124gr, works good, just need an OAL out to 1.180 or so it will pick the OAL for you. AutoComp and HS6 both work almost as good as Silhouette. IMHO. If you have excess crimp you could be losing 60fps, also you will get more velocity out of a Zero bullet than an MTG of he same weight. I test all my loads with WSPP, the rifle primer masks the pressure signs, once proven I do a final crono with the Rifle Primer just to make sure its still in the desired pf range. If I run out of rifle I can use SPP without fear of too much pressure or going minor. Edited July 14, 2013 by CocoBolo Link to comment Share on other sites More sharing options...
chuckols Posted July 16, 2013 Share Posted July 16, 2013 Poppa Bear has hit a home run! Link to comment Share on other sites More sharing options...
n2ipsc Posted July 16, 2013 Author Share Posted July 16, 2013 No I idea why you would be dinking around with Loud shot if you have Silhouette... Just had a couple of pounds laying about and decided what the heck...couldn't figure out any other good use for it... Link to comment Share on other sites More sharing options...
CocoBolo Posted July 16, 2013 Share Posted July 16, 2013 No I idea why you would be dinking around with Loud shot if you have Silhouette... Just had a couple of pounds laying about and decided what the heck...couldn't figure out any other good use for it... Hey, that's just part of my humorus style, I tried a lot of powders to find out I didn't like a Shorty, gun, and discovering Silhouette was pure accident, at a match a Revolver shooter put me on to it. Loud Shot aka Long Shot works ok in 38S, again not a favorite, AA#7, or N105. You are shooting a Holley Joe, so its already tooth rattling loud, so why not, shoot it up at a local match. Link to comment Share on other sites More sharing options...
wes777 Posted September 6, 2013 Share Posted September 6, 2013 Well, here's a new experience... Working up loads (well, trying to, anyway...keep reading) with Longshot for my Limcat (full-length, V-6 ported, 4-chamber comp). 124g MT Gold JHPs, once-fired Federal cases, WSR primers, 1.165" OAL, Oehler 35P chrono. Everything progressing nicely... 7.0 gr Longshot - 1311fps/34fps SD/162PF 7.2 gr Longshot - 1324fps/28fps SD/164PF 7.4 gr Longshot - 1348fps/18fps SD/167PF So far, so good; velocities increasing reasonably linearly, std dev's tightening, seemingly closing in on good load, would like a little cushion on PF, so, a little bit more should get me there... 7.6 gr Longshot - 1298fps/49fps SD (!) 7.8 gr Longshot - 1299fps/35fps SD (!!) Chrono'd regular load (7.8 Silhouette) as check - spot on @1378 fps... Hmmmm... Back to the bench, calibrate scales (yes, two, as cross-check), load two more test batches @ 7.6 & 7.8, weighing each charge...and... 7.6 gr Longshot - 1299fps/57fps SD (!) 7.8 gr Longshot - 1307fps/35fps SD (!!) Chrono'd regular load (7.8 Silhouette) again as check - spot on @1380 fps... So, if this (counter-intuitive!) data is to be believed, one would have to be well north of 8gr with Longshot to make, oh, say, 170pf in my particular gun, but am guessing, and I think correctly, that at some point not very far above 7.8 things are going to spike dramatically. 7.4gr load too close to 165 for comfort. My search-foo may be lacking, but I can find nothing anywhere noting this phenomena (more powder = LOWER velocities?!) with Longshot in Major 9. Has anyone else experienced this issue? "Recovering" velocities by going higher yet on charge weight? Keen to hear any feedback... I thought that this was the issue at around 8 gn longshot under a 115. Made 155pf. thought that I had lost my mind. So, I crammed more powder in the case and went for a super/comp load weight. 9/9.5/10 gn, out of pure frustration. Guess what 10 gn of longshot looks like in a 9mm case. One word description: FULL. Working between 8-10 gn, velocities rose, piqued, then dropped. Primers all look ok, no flow. I might have a bad batch of powder, or a bad box of bullets... trying to work out which one now. Link to comment Share on other sites More sharing options...
Sherwyn Posted September 6, 2013 Share Posted September 6, 2013 Well, here's a new experience... Working up loads (well, trying to, anyway...keep reading) with Longshot for my Limcat (full-length, V-6 ported, 4-chamber comp). 124g MT Gold JHPs, once-fired Federal cases, WSR primers, 1.165" OAL, Oehler 35P chrono. Everything progressing nicely... 7.0 gr Longshot - 1311fps/34fps SD/162PF 7.2 gr Longshot - 1324fps/28fps SD/164PF 7.4 gr Longshot - 1348fps/18fps SD/167PF So far, so good; velocities increasing reasonably linearly, std dev's tightening, seemingly closing in on good load, would like a little cushion on PF, so, a little bit more should get me there... 7.6 gr Longshot - 1298fps/49fps SD (!) 7.8 gr Longshot - 1299fps/35fps SD (!!) Chrono'd regular load (7.8 Silhouette) as check - spot on @1378 fps... Hmmmm... Back to the bench, calibrate scales (yes, two, as cross-check), load two more test batches @ 7.6 & 7.8, weighing each charge...and... 7.6 gr Longshot - 1299fps/57fps SD (!) 7.8 gr Longshot - 1307fps/35fps SD (!!) Chrono'd regular load (7.8 Silhouette) again as check - spot on @1380 fps... So, if this (counter-intuitive!) data is to be believed, one would have to be well north of 8gr with Longshot to make, oh, say, 170pf in my particular gun, but am guessing, and I think correctly, that at some point not very far above 7.8 things are going to spike dramatically. 7.4gr load too close to 165 for comfort. My search-foo may be lacking, but I can find nothing anywhere noting this phenomena (more powder = LOWER velocities?!) with Longshot in Major 9. Has anyone else experienced this issue? "Recovering" velocities by going higher yet on charge weight? Keen to hear any feedback... My experience has been very similar in testing long shot. Had a load I really liked worked up in cool weather...dropped 100 fps in warm weather. In testing afterwards it was repeatable. Once load hit peak, any amount of additional powder made almost no difference and little or no pressure signs. Sherwyn Link to comment Share on other sites More sharing options...
Got Juice? Posted September 7, 2013 Share Posted September 7, 2013 Internal ballistics. Once the gas pressure from the burning powder overcomes the crimp holding the bullet in the brass and propels the bullet out of the case mouth, any excess powder is no longer in a confined burning area. It will continue to burn slightly down the bore of the pistol, and some half burned flakes is evidence that is happening (and wasted). Link to comment Share on other sites More sharing options...
Got Juice? Posted September 7, 2013 Share Posted September 7, 2013 Another side note/observation. I can make major PF in my Aperio with 4.7gn titegroup under a 180gn Berry's. But the gun behaves like total crap. Snappy recoil, bad slide dynamics etc. Load development led me to increase my charge to 5.2gn. Now the gun settles inbetween shots perfectly. Counter intuitive that more powder will smooth out a recoil impulse but it does. 197PF. What happens with this 'hot' load is the powder burn rate does not change, but the available case volume for the expanding gas volume is less(and slows down the expansion cycle). This creates a condition where the expanding gasses do not overcome crimp as easily since there is less initial 'free space' in the cartridge fir the gas to exert pressure on. A good analogy is to exert a force of 5lbs of force on your friends nose with your fist for 5 minutes. No damage will be done. Now change the equation. Apply the total force excerted on your friends nose over the last 5 minutes, but decrease the time used to deliver the force to 1 second......you'll break his nose. Link to comment Share on other sites More sharing options...
MoonJeong Posted March 8, 2015 Share Posted March 8, 2015 yeap i hit plateau at 7.4 giving me 165 PF, anything more and PF goes down... and something funny - last week it was 30 degrees and was at 165 PF, today was 75 degrees and got down to 160 PF, then increased to 8 grains and got 155PF... so i guess this is no good... will try 135 grain bullets... perhaps that works... Link to comment Share on other sites More sharing options...
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