eddiegunks Posted August 11, 2012 Share Posted August 11, 2012 hi all, i bought a nice 38 sc/tj caspian open gun recently. it has a barrel with 4 ports and a comp. the previous owner said his loads were 9.8-10gr of 3n38 with a 124gr bullet. so i figured i would use this info. i finally got out and was able to chrono some loads today. i used a prochrono. overcast day....basically a light rain falling. 73 degrees F. i am using 125 gr jacketed hollow point zero bullets. 38TJ brass. small rifle primers by winchester. .378 crimp. 1.235 OAL. 3n38 powder. i shot 3-4 rounds of each of the below loads. took the average. 9.4gr = 1265 fps 9.6gr = 1310 fps 9.8gr = 1330 fps 10 gr = 1330 fps i do not seem to be getting a big advantage with the slightly more powder. do i stop here or try a few grains more? the primers do not show excessive pressure issues. the cases had a bulge at the base about .393-.395. they all seemed uniform and at all load weighs the bulge was pretty much similar. is this normal? (the brass the previous owner included had a slightly less bulge on some of the cases.....others were right about what i am seeing.) am i on the right track? what is your suggestions? thanks eddie Link to comment Share on other sites More sharing options...
OperationHitFactor Posted August 11, 2012 Share Posted August 11, 2012 Hmm, I'd go back over the press step by step to make sure everything is right. Then start at 9.8, then do 10.0 followed by 10.1 record your results and see what happens. When I encounter things like this I start back at square one. I usually find it is user error on my part or an equipment malfunction. 3N38 shouldn't be plateauing at that velocity. Link to comment Share on other sites More sharing options...
eddiegunks Posted August 11, 2012 Author Share Posted August 11, 2012 Hmm, I'd go back over the press step by step to make sure everything is right. Then start at 9.8, then do 10.0 followed by 10.1 record your results and see what happens. When I encounter things like this I start back at square one. I usually find it is user error on my part or an equipment malfunction. 3N38 shouldn't be plateauing at that velocity. thanks. i am using a single stage press. so i will be having to reset it for the seating and crimping part. i am using dillon dies. anything in particular you would suggest i keep an eye out for? what kind of user error or equipment malfunction have you seen in the past? just curious what i may be looking for. thanks eddie Link to comment Share on other sites More sharing options...
OperationHitFactor Posted August 11, 2012 Share Posted August 11, 2012 What are you using to drop your powder? Also scale? Usually it's in the powder weight/drop area as this is where you are making changes. Link to comment Share on other sites More sharing options...
al503 Posted August 11, 2012 Share Posted August 11, 2012 (edited) I've found 3n38 to be very consistent from lot to lot but you might have a slower lot than the previous owner. Try a batch of 20 at 10.2 grains. 3n38 is a very safe powder and I wouldn't be too alarmed until you get closer 10.5. I would weigh every charge and make sure it's consistent. Was the previous owner using round nose bullets? If so, they are usually longer than JHPs and would lead to higher initial pressure spike when loaded to the same OAL. Edited August 12, 2012 by al503 Link to comment Share on other sites More sharing options...
OperationHitFactor Posted August 11, 2012 Share Posted August 11, 2012 Also what primers are you using. I like small rifle primers and other guys have success with magnum pistol primers. If you are using small pistol sometimes it's not enough to get a good burn with a slow powder like 3N38. Link to comment Share on other sites More sharing options...
eddiegunks Posted August 11, 2012 Author Share Posted August 11, 2012 thanks. sorry for the delay. i was loading some more rounds and waiting for the rain to let up.... i am using winchester small rifle primers. i have weighed each individual charge this time out. i checked it on my rcbs beam style scale. calibrated it before i started. i was not using a drop tube this time. i poured it from the scale tray......i tried to be as careful as possible. my last batch i used a lyman #55 and dropped the powder directly into the case from the measure. 3 shots per powder charge. this last trip was as follows: grains = fps 9.8gr = 1336. 1326. 1304 10 gr = 1337. 1322. 1310 10.1 gr = 1336. 1317. 1328 10.2 gr = 1333. 1356. 1317 i may borrow another chrono to eliminate that possibility. i will also load up a few more as suggested above. thanks for the help. i am just trying to be cautious so i do not hurt myself or the gun with ignorance.... keep em coming. eddie Link to comment Share on other sites More sharing options...
OperationHitFactor Posted August 11, 2012 Share Posted August 11, 2012 Well you've got me stumped. Those velocities are off, not way off, but off. This could be an issue more with lighting on the chrono or some other random event. 10.2 gave you 1356 once outside of that, everything else is the same ballpark. Are you measuring OAL on each round for consistency after crimp stage? Make sure it's not getting any OAL variations. Also maybe try a tad more crimp. Link to comment Share on other sites More sharing options...
eddiegunks Posted August 11, 2012 Author Share Posted August 11, 2012 Well you've got me stumped. har har har! me too. that is why i asked. yes, the AOL are all very close. this last time they were 1.233 to 1.235. i measured them before crimp and after. i will try and borrow a chronograph and see if that make s a difference. maybe the crazy weather affected the chrono. i will also try and borrow another scale to verify mine is actually on..... that is all for today. maybe i will get out again tomorrow and see what develops. cheers eddie Link to comment Share on other sites More sharing options...
wide45 Posted August 13, 2012 Share Posted August 13, 2012 How close is your chrono to muzzle? If too close, you are just reading the blast, and won't get bullet velocity. Link to comment Share on other sites More sharing options...
Action Pistolero Posted August 13, 2012 Share Posted August 13, 2012 I never had much luck using a chrono in the rain no matter how light. Are you using the same bullet as the previous owner? The jacket material may be different and causing your problem. Link to comment Share on other sites More sharing options...
eddiegunks Posted August 13, 2012 Author Share Posted August 13, 2012 (edited) okay. i verified the scale was on. i borrowed another chrono. there was a slight discrepancy with mine so i will try the other. it has finally stopped raining. tomorrow i hope to have my loads all figured out and ready to take to the matches...stay tuned. cheers eddie Edited August 13, 2012 by eddiegunks Link to comment Share on other sites More sharing options...
eddiegunks Posted August 13, 2012 Author Share Posted August 13, 2012 (edited) i tell you, the weather has it out for me. nice sunny day....as soon as i get all ready for the range the clouds roll in. no problems. it did not rain and all was good. phew! i am about 14-15 feet from the chrono. i tried again with the borrowed chrono. with a crimp of .378 and an oal of 1.234 i got 9.8gr = 1281. 1288. 1283 fps 10 gr = 1317. 1326. 1313 fps 10.2gr = all less than 1300fps....not sure what happened here! with a crimp of .374 9.8 gr = 1276. 1280. 1285 fps 10 gr = 1297. 1307. 1331 fps 10.2 gr = 1317. 1327. 1341 fps so it appears i am slowly picking up velocity. so my questions are now: do i keep bumping it up .1 of a grain and see if i can get major PF (with a slight margin of error)? is it still safe (primers all look good). do i use .374 as my crimp? can it handle a bit more crimp? if so how much? thanks eddie Edited August 13, 2012 by eddiegunks Link to comment Share on other sites More sharing options...
G-ManBart Posted August 13, 2012 Share Posted August 13, 2012 You're shortcutting a couple of steps. Set the powder measure for 10.0gr, throw two or three that you dump back in the measure. Throw ten charges, weigh all ten together and divide by ten to get an average weight. Do that probably two or three times (3 averages should be okay). Now load 20 rounds and chrono all 20 to get an average velocity. Then, repeat the process with 10.2gr, and see what you wind up with. Right now you're simply dealing with sample sizes that are too small to really know what's going on. Also, are you using new, or used brass? Load development is much easier with new brass, and you will usually see something like 30-50fps higher, and much more consistent ES and SD in a cartridge as fast as 38TJ at Major. Link to comment Share on other sites More sharing options...
G-ManBart Posted August 13, 2012 Share Posted August 13, 2012 P.S. go back to .378" crimp....trying to increase velocity with crimp doesn't work reliable with taper crimp and non-cannelure bullets (which require a roll crimp). Link to comment Share on other sites More sharing options...
eddiegunks Posted August 14, 2012 Author Share Posted August 14, 2012 Thanks g man I will try it in the morning. So i should throw ten charges, all together, and weigh them? So if all is perfect i will have 100 gr. then divide by 10. What is the purpose? Thanks. It is new brass. I will do as you described above. Cheers. Eddie Link to comment Share on other sites More sharing options...
Whoops! Posted August 14, 2012 Share Posted August 14, 2012 I've seen this exact same problem before. In the case I saw, the barrel was worn out. The only fix was to replace it. I'm not saying you have the same issue, but 10 grains of 3n38 behind a 125 grain should definitely get you much more velocity than that, even with small pistol primers. Link to comment Share on other sites More sharing options...
shootingchef Posted August 14, 2012 Share Posted August 14, 2012 From what little I have seen of 3N38, he is actually hitting the same numbers I do. I run 10.5 behind a MG124 and make 1350 out of my 3 hole SV. I know folks who run over 11 grains out of a 4 hole SV and are barely getting to 180 PF. Whereas you take the same powder from from a different lot, and you make major with 10.1, 3N38 is not as consistent from lot to lot as we would like. Link to comment Share on other sites More sharing options...
Whoops! Posted August 14, 2012 Share Posted August 14, 2012 (edited) That is wicked, I just used 10 grains to make 170 PF out of a 2 hole shorty open gun with 121 grain hornadys. Very substantial difference in that regard. But, the velocity wall still says to me there is an issue besides the powder. In the case I saw, it was the barrel. Edited August 14, 2012 by Whoops! Link to comment Share on other sites More sharing options...
eddiegunks Posted August 14, 2012 Author Share Posted August 14, 2012 Hhhmmm? And how do we tell a worn out barrel? Thanks Link to comment Share on other sites More sharing options...
eddiegunks Posted August 15, 2012 Author Share Posted August 15, 2012 (edited) You're shortcutting a couple of steps. Set the powder measure for 10.0gr, throw two or three that you dump back in the measure. Throw ten charges, weigh all ten together and divide by ten to get an average weight. Do that probably two or three times (3 averages should be okay). Now load 20 rounds and chrono all 20 to get an average velocity. Then, repeat the process with 10.2gr, and see what you wind up with. Right now you're simply dealing with sample sizes that are too small to really know what's going on. Also, are you using new, or used brass? Load development is much easier with new brass, and you will usually see something like 30-50fps higher, and much more consistent ES and SD in a cartridge as fast as 38TJ at Major. okay. just got back in. thanks for all the help. this is what happened today. i followed g man's post. (.378 crimp) i dropped 10 charges(10gr) and weighed all 10, three times, then and divided by 10 the average was: 10.14, 10.11 and 10.05gr. i dropped 10 charges(10.2gr) and weighed all 10, three times, then and divided by 10 the average was: 1026, 10.29 and 10.26gr. i then loaded 20 rounds with 10gr. the average chrono time for all 20 was 1324.2 fps. i then loaded 20 rounds with 10.2 gr. the average chrono time for all 20 was 1338.6 fps. the two groups i shot were fairly tight....most were touching. i was about 15 feet from the chrono and 30 feet from the target. thanks again for all the help. eddie Edited August 15, 2012 by eddiegunks Link to comment Share on other sites More sharing options...
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