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.38 Supercomp Load Development


XRe

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I went out with DJPolo yesterday to chrono up a bunch of stuff I've been concocting back in the lab, trying to find appropriate Major PF loads for my new open gun. Chet was kind enough to indulge my obsessive/compulsive anal-retentive project - I ended up chrono'ing 300 rounds of .38 Supercomp stuff (5 charge weights of 6 powders - 10 rounds each). My results follow - interestingly, I found all of this data on this web site, and it resulted in my being able to develop 6 safe sets of starting loads to test with in my gun - this only applies to my gun. But.... the data is out there :D Once I updated the table I made with my data below, I'll add a post to this one with the whole set of data I gathered from here and Jeff Maass's site to decide how and where to start, etc....

Common factors in each round - 125gr HAP measuring .356, virgin Starline .38 Supercomp brass, WSR primer, 1.250" OAL, .378" crimp. Average velocities and PF are listed, plus SD and ES... in the format "weight - velocity - PF - SD - ES"...

3N37

7.8 1270.8 158.9 13.7 39.1

8.0 1294.7 161.8 11.7 37.1

8.2 1339.8 167.5 8.9 26.8

8.4 1362.2 170.4 7.0 25.7 - primers starting to slight very slight cratering

8.6 1389.3 173.7 13.3 40.0 - primers showing slight cratering, 4 out of 10 rounds

N350

7.3 1322.5 165.3 12.8 39.9

7.5 1342.5 167.8 10.1 30.4

7.7 1376.1 172.1 7.4 28.4

7.9 1392.2 174.0 7.9 24.4

8.1 1411.2 176.4 19.7 73.8 (one chrono'ed real low - 1364.2...)

3N38

8.8 1264.8 158.1 9.0 34.4

9.0 1287.9 161.0 3.9 11.6

9.2 1311.9 164.0 14.7 49.1

9.4 1331.3 166.4 8.2 27.1

9.6 1354.7 170.0 9.9 33.1

N105

9.5 1358.0 169.8 10.9 34.2

9.7 - natch, lost the data - roughly 173 PF

9.9 1396.2 174.5 10.2 37.6

10.1 1414.7 176.8 9.0 29.3

10.3 1429.7 178.7 17.2 50.0

7625

7.0 1324.4 165.6 10.9 28.7

7.2 1395.1 168.1 12.3 45.9

7.4 1367.5 170.9 7.0 19.4

7.6 1394.5 174.3 13.8 48.4

7.8 1405.2 175.7 5.9 16.0

4756

7.9 1281.1 160.1 15.4 45.4

8.1 1308.2 163.5 11.4 33.2

8.3 1323.5 165.4 19.0 51.1

8.5 1351.4 168.9 12.4 42.2

8.7 1378.3 172.3 10.8 29.3

I was able to find a 170-ish PF load of each. Next step is to load up a hundred or so of each one, and go head to head. At this point, in my gun, there's not a whole lot of difference between each one. What I can say - the 160-ish PF charge of 3n38 feels like nothing. The starting charge of N105 gave me the same impression, and was already 170PF :blink: It took a tenth of a grain less of N105 to hit 170PF than 3N38 in my gun, with the lots of powder I was using. It took a full grain less of N350 than 3N37!!! 7625 impressed me at how nice it shot. 4756 isn't as nice as the others, and was the only one that stood out as being somewhat different from the other loads - it was also the most inconsistent (and, no, I didn't spill any powder - I was very careful :) ). 3N37 is snappy, relative to the others, and was the only one that resulted in any primer related signs of pressure issues - it may be too fast, in the end. That's about the limit of what I could tell from just shooting rounds over the chrono.

Edited by XRe
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7625 shoots good but in my super comp its not as accurate as any of the other loads ive shot.

HS6 was real good accuracy wise, felt good and is cheap...only slightly dirty

Accurate arms number 7 is the most accurate powder ive tried but with charge weights exceeding 10 grains and not all shops in my area carrying accurate powders(not to mention the intense dirtiness of the powder) made me switch to others.. imo, aa#7 feels really good.

so as an economy thing coupled with easy to get powders, i use HS6 for now and power pistol as a back up.

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Well, next up is accuracy test and a head to head, blind comparison for feel. I was happy that a less expensive powder feels pretty good. 4756 is definitely usable, but 7625 seemed better... with as wildly inconsistent as 4756 seemed in this gun, it's probably not going to survive the elimination challenge.... :)

Used to use HS-6/540 in 9x21, and it worked OK there - I ended up switching to 3N37, though. Cleaner and more effective in my comp in that gun.

Easy to get, and economy are, of course, important to me in this endeavor. I don't mind paying for VV powder - availability has me slightly concerned. I'm hoping to have 2 to 3 working loads that I can switch in between without issue. With as close as these powders seemed to feel to one another, that shouldn't be any issue :)

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  • 1 month later...

In this thread on load testing, I added some more info on the tests that followed what was above. To get it all together, I've replicated it here (especially since the thread author on the other thread asked that it possibly be deleted??? Don't want it to away...). Plus, it's very relevant to this thread :)

---- begin copied content -----

Loaded up 6 different powders w/ one bullet weight and found 170PF for each. I discarded two powders outright from that testing - one started to show pressure signs, and the other was more obviously flippy and harsh in the hand during chrono testing.

Then I loaded up loads of each of the four remaining powders at 170PF, and shot them in a blind comparison during a match, and took notes on which ones I liked. Then, I went out a second day, and shot another blind comparison shooting some drills. I had two other shooters - one a complete noob to Open guns, and another more experienced shooter - do the same, and took their info as additional points to consider. That narrowed it down to two powders. I then went out a third day and shot 4 Bill Drills (at 50, 25, 15, and 7 yards) with each, and half a Vice Pres (2 on each at 7 yards) and took notes - I did this with all four powders, and knowing which one was which (ie, not blind), so that I could compare. I then shot the previous "best two" with some movement drills and off balance stuff, to evaluate subjective recoil.

The result? I still eliminated the same 4 powders, in the end, and was left with two that consistently cycled the gun straight up and down. The only difference was how flat it shot. The flatter one had about 50% less dot rise, and is about 50% more expensive.

So, for 125 HAPs in my gun, 3N38 worked best, followed by 7625. I consistently was able to shoot faster, more accurate drills at all yardages with these two powders. Out of the powders I eliminated, I liked them in this order: N105 (less predictable, but very soft), N350 (relatively harsh, and inconsistent movement), 3N37 (pressure signs), 4756 (flippy and quite harsh).

The next test?? Try 121s and 115s with 3N38, 7625, and N350 (cause I've got a good amount of it left) :)

It was really windy out the day I did the first batch of shooting tests. I shot a 10 shot group w/ each one at 50 yards using my bag as a rest. Being as it was gusting in the 30+ mph range, I didn't take them *too* seriously, cause I didn't shoot them too well, relatively speaking. But, 7625 was the largest group at 3", including whatever might count as a flier. 3N38 was the best, at 2 9/16", and N105/N350 were both at 2 3/4". That's pretty close across the board. However, most of the 3N38 rounds were clustered in a 1.5" group, with four outliers - I'm not reading too much into that, but it had the impression of being slightly more consistent.

Also - the gun was sighted in for N350. 7625 and N350 shot to same POA. 3N38 and N105 grouped about 4-5" lower at 50. I attribute this to the greater volume of gas in both of those loads keeping the muzzle slightly flatter until the bullet has exited the barrel - maybe that's hooey, but... ;)

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XRe what pistol configuration do you have ?

I have a bunch of rounds as well for my two Bedells shorty 38 SC (Starline TJ)that I expect to be home in a couple weeks....will post my results when I do my testing....

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  • 2 weeks later...

For what ever reason I keep coming back to N-350.

The gun is a 5" with six a six port comp straight up.

No funny holes in the barrel/slide and N-350 works well with 115 or 125 GRN bullets.

But I'm an C class open shooter too.

FM

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  • 3 months later...

Resurrecting this thread from the dead. I was motivated by Guy Neill's latest article on using 2400 in .38 Super. Bought a pound to try out. The short answer - it simply isn't going to work in my gun... The common factors below - 125gr HAP, virgin Starline .38 SuperComp brass.

WSR primer

10.2 1032 avg - wouldn't cycle the gun

10.5 1057 avg

10.8 1081 avg

11.1 1112 avg

11.4 1145 avg

These loads left a dramatic amount of unburned powder behind. After consultation with Guy, we feel that the hybrid ports in my gun (see the thread mentioned above for details on the gun config) are "uncorking" the barrel too soon, relieving the pressure required to completely ignite and combust the powder.

As a further experiment, I tried a CCI 450 Small Rifle Magnum primer, to see if I'd get better ignition:

CCI 450 primer

11.1 1113 avg

11.4 1142 avg

11.7 1152 avg

12.0 1188 avg

12.3 1206 avg

I can fit 13.5 or so grains in the case, with it mounded at the top. 12.3 is getting *awful* close. Still loadable, but....

The Small Rifle Magnum primer definitely provided better ignition - I had much less unburned powder accumulation, even with a load weighing a grain more than previous tests. As you can see, though, it didn't make any difference in velocity. Out of 50 test rounds, I had 2 failures to ignite (which ignited on a 2nd primer strike). These were not high primers (I triple checked the rounds after loading them). So, that primer isn't going to work in my gun - a 4% rate of not firing isn't too nice in a match context...

Anyhow, this probably isn't going to be a good powder for hybrid guns - YMMV, of course.

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Dave, I tried H110 and 2400 in my hybrid super with about the same results...12 grains of powder and 9mm ballistics(weak 9mm at that)

I would like to try them in a unported 5.5 inch gun...might be worth looking into.

Harmon

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I would like to try them in a unported 5.5 inch gun...might be worth looking into.

Guy told me that he's doing his development in a 5" unported barrel, so.... apparently to the ultra-slow pistol powders, that last inch is pretty important... ;)

It was a fun experiment, though.... :D

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  • 6 months later...

I would also think that Silhouette, which supposedly duplicates the old Winchester Action Pistol (WAP) would also be worth a try. There is data online for 9X23 using WAP.

If I am not crazy, the 9X23 and the 38 Supercomp are the same round. I have used some Win. White Box 9X23's and they all chrono'ed in the mid to high 1400's with one round going over 1500fps in a 5"bbl 1911 single stack! Of course the Winchester brass is somewhat thicker in the "web" area and when used with small rifle primers will be safe to 50,000 psi... or so I read anyway.

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Harmon - yep, indeed. 8.1gr w/ a HAP 125 was the load I ran at the Open Nationals (173 PF there). The Zeros I just got in are a tad slower (the bullet is shorter with more weight out front, so more room in the case), so I'll be bumping that up a tenth or so...

Justsomeguy, you're crazy - they're not the same round :D 9x23 is a tapered round like the 9mm, and as such has a larger base size than .38 Supercomp. .38 Supercomp is .38 Super w/o the rim (and a slightly thicker internal case web), and so is a straight walled cartridge. They're very similar, overall, but not the same. 9x23 apparently has slightly smaller internal volume, and should require slightly less powder than .38 Supercomp to make the same velocity.

ETA - Silhouette might be a reasonable choice in this gun, as well. As you can see, I tested a bunch of stuff - the stuff I could get ahold of most easily. I haven't yet found Silhouette in a store around here, but I admit I haven't looked real hard, either. However, 7625 works so well in this gun, and is pretty cheap (and clean) that I'm hesitant to really go searching again for a while... :D

Edited by XRe
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I have an SV IMM with the Scheuman hybrib barrel with ports. I tried 7625 and had pressure problems. I have settled on VV 3N38 10.2 gr, Starline SC brass, Win SRP and Zero 125 JHP loaded to 1.250. It is the most accurate load in my gun. I was told that Armscor rimless 38 super brass lasts longer and usually you can drop your powder charge

.2 to.3 grains. Has anyone found this to be true with Armscor?

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In a barrel with that many holes that start that close to the bore, you're going to need slower powders to reach proper velocity safely. 7625 would definitely not be a powder of choice in an IMM w/ the full port configuration. My understanding is that SV suggest using only 3N38 in that configuration.

I've never used Armscor brass - there are probably threads on this forum that deal with it, though. I use Starline .38 Supercomp brass - I've always had great results with it - it lasts a super long time (I have cracked exactly one case in approximately 60,000 rounds and 5,000 new cases). I lose it long before it gives up....

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I was told that Armscor rimless 38 super brass lasts longer and usually you can drop your powder charge .2 to.3 grains. Has anyone found this to be true with Armscor?

Starline is better than AP IMHO. I've never had issues with Starline. I have had issues with AP. Internal volume seems to be about the same. 38 Super Lapua and Hornady TJ brass has less volume and need less powder for the the same PF.

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Harmon - yep, indeed. 8.1gr w/ a HAP 125 was the load I ran at the Open Nationals (173 PF there). The Zeros I just got in are a tad slower (the bullet is shorter with more weight out front, so more room in the case), so I'll be bumping that up a tenth or so...

Justsomeguy, you're crazy - they're not the same round :D 9x23 is a tapered round like the 9mm, and as such has a larger base size than .38 Supercomp. .38 Supercomp is .38 Super w/o the rim (and a slightly thicker internal case web), and so is a straight walled cartridge. They're very similar, overall, but not the same. 9x23 apparently has slightly smaller internal volume, and should require slightly less powder than .38 Supercomp to make the same velocity.

ETA - Silhouette might be a reasonable choice in this gun, as well. As you can see, I tested a bunch of stuff - the stuff I could get ahold of most easily. I haven't yet found Silhouette in a store around here, but I admit I haven't looked real hard, either. However, 7625 works so well in this gun, and is pretty cheap (and clean) that I'm hesitant to really go searching again for a while... :D

I read somewhere that the new Winchester Brass is no longer labeled as 9X23 but now as something else like 9mm Supercomp or some such... thus the confusion. And so I guess I am loopy! And yes, 9X23 IS a tapered case. It's still a pretty good round though, and the case is still a bit stronger than the others in this length and caliber. I have 1000 new brass from Winchester for this round, plus about a hundred from the WWB stuff I was testing when I reamed a 38 Super barrel for the experiment. I still need a full length resizing die for the stuff so I can reload for it. Do you know where I can get one?

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Dammit, stop drifting my thread!!!!!!!!!!!!!!!!

:D

The only brass that's labeled as 9 Supercomp is Starline. There's a thread on the forum about it. You use a 9x19 sizing die. Search, man...

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Dave, how many different lots of 7625 have you had a chance to try so far? I used to load 7625 in my open gun but the density and burn rate varied so much lot to lot that some would just barely make major with a full case and some were making 170pf at 80% full. Burned clean and felt good, though. Just wondering how much variation you are seeing.

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