38 SC Load Questions

[trodrig]

Hi all! I received my Trubore from Dawson this past Friday and am working up some loads for it. Pics of the gun will be coming soon! Here's a summary of what I'm going to test out. Going slow since this is my first time loading for 38 SC and I know it's a different animal from the low pressure 45 I'm used to!

Common Factors:

New Starline 38 Super Comp brass

115 grain Montana Gold JHP

1.240" OAL

0.378" Crimp

Loads:

Longshot: 6.5gr, 6.8gr, and 7.1gr

SR7625: 6.0gr, 6.2gr, 6.4gr, and 6.6gr

SR4756: 8.0gr, 8.3gr, and 8.6gr

The SR4756 loads are all REALLY full. I've attached a pic of a case with 8.6 grains in it. Hope I uploaded it correctly....

I'm not use to compressed loads like this and just wanna make sure this is not an issue. Dawson recommended 9.5 grains with 115gr bullets but I'm just not use to seeing cases this full and am kinda nervous.

Thanks for the help!

Trodrig

[al503]

It's not an issue besides having to slow down your indexing to keep the powder from slinging around. I was loading ~9.0 of 4756 and the case was pretty full. 9.5 would probably get you to the rim.

[Front Man]

Place the bullet on the case before indexing.

FM

[XRe]

Couple of observations - that's about normal for a 4756 load. Its a bulky powder. Also, you're going to need more 7625 than what you have listed. My loads for a 125gr bullet are in the 8.2gr range (though I have lots of holes - 7.5 is probably a good place to start w/ a TruBor).

[trodrig]

Thanks guys! So, it's just the nature of 4756 that it fills the case to the top?

Trodrig

[EZ Bagger]

I agree that your 7625 loads are probably too low.

For a 6" unported barrel, I still use over 7 grs

For my stroker with a short barrel and 2 holes in the barrel I use 8.65gr with the 115's. Powder spill is an issue. You will make a mess.

May still be worth documenting some of those light loads for steel matches or other places where major power factor is not an issue.

[trodrig]

Thanks Dave! Looks like you answered my question about that just being the nature of 4756 as I was typing it!

I figured I was going to be way under major with the weights of 7625 that I picked but I just wanted to go slow. Is 7625 a good candidate for minor steel loads?

I'll hopefully chrono these today and work towards the 7.5 range you suggested for major!

Thanks!

Trodrig

[XRe]

So, it's just the nature of 4756 that it fills the case to the top?

Yes. Compressed loads are your friend Actually, in many ways, these loads are safer than loading for .40. Sure, they're relatively high pressure, etc - but there's no way to throw a double charge, and small errors in the powder charge don't suddenly result in very negative consequences

[trodrig]

Thanks Dave! That's true, there's no way to double charge with this powder! Just wanted to make sure I wasn't way off base with the case being that full. Sure is nice to have this resource to get advise from! I appreciate it!

I'll post the chrono results later. I'm chompin' at the bit to get out and shoot this thing! I've had it for 5 days now and only fired one mag through it!!

Trodrig

[trodrig]

I was able to chrono pretty much all of my loads this evening! I tell ya, fall is upon us because the sun is going down quick and the Chrony don't like to work too well in the shade!

Anyway, as expected, most of my loads were WAY light! Although there was one standout accuracy wise. Here's the results...I'm only posting the higher PF results:

Longshot

7.1grains => 1370fps (157.5pf)

SR4756

8.3grains => 1380fps (158.7pf) VERY accurate! All holes touching at 20 yards!

8.6grains => 1406fps (161.6pf)

SR7625

6.6grains => 1350fps (155.2pf)

Both IMR powders were pretty accurate across the board but 8.3 was really good. I'm gonna push all of these loads higher and load up another batch for this weekend! I'm thinking 9.2 or 9.3 with SR4756 should get me to major and maybe 7.6 for Longshot? I'm thinking 7625 is probably going to need 7.5+

Trodrig

[EZ Bagger]

Don't get too far ahead of yourself by going up a full grain at a time.... All those poofy rounds also give you a chance to break the gun in nice and slow, getting used to the trigger, etc.

Any of those load feel really soft? Might want to keep track of those for plinking/steel.

[AlamoShooter]

I like the 7625 for major loads, but not so much for steel. Not a big dif , but to get what I like the best out of my steel loads I use Hog Universal 6.4 with a 95 gr zero

I just recently have ben trying the 115 and I need 7.6 to make 166 pf in 7625 BUT the 121 & 124 bullets "feals" better to me.

my barrel only has one hole and a three chamber comp

Watch for the primers, you may end up with them flowing back into the firing pin hole if you dont use rifle primers.

Next time I see you ask to try my loads or my gun, and that can help with lots of tryalls

Jamie

[trodrig]

Good point EZ! I'll be moving up slow watching for pressure along the way! Now that you mention it, I did notice that 8.3 of 4756 was very soft. 8.0 was too but I think it was too light for the gun as it wasn't cycling the slide far enough to strip the next round off of the magazine reliably. Either it's too light or maybe the gun needs to be broken in more?

Trodrig

[EZ Bagger]

8.0 was too but I think it was too light for the gun as it wasn't cycling the slide far enough to strip the next round off of the magazine reliably. Either it's too light or maybe the gun needs to be broken in more?

Trodrig

Yep, probably just too light for the gun. Not a killer, though. If it were making major you'd track down a spring combo that would work :-)

[trodrig]

Thanks for the info Jamie! I'd like to try some of your recipes! I'll look for you at the next Texas Steel match.

Trodrig

[AlamoShooter]

The event at the Bullet Hole this Sundayt may/, will, be worth the drive. I am helping with that as an RO on Sunday = fill up the car with shooters and make the trip.

Jamie

[trodrig]

I really wanted to go to that match but my daughter's 13th birthday party is that day so I won't be able to. I'll catch ya at the next one at Cedar Ridge though! Hopefully by then I'll have had a chance to work up further with the 3 powders I've got right now for comparison.

Thanks,

Trodrig

[trodrig]

Well, I just thought I'd update this thread with some new results.

I'm up to major PF with both SR4756 and Longshot. It took 9.1grains of 4756 and 7.9grains of Longshot. Here are the specifics:

9.1 grains SR4756; 115grain MG

Low: 1444 (166pf)

High: 1479 (170pf)

Avg: 1460 (167.9pf)

ES: 35.13

SD: 12.2

7.9 grains Longshot; 115grain MG

Low: 1446 (166.3pf)

High: 1485 (170.7pf)

Avg: 1467 (168.7pf)

ES: 39

SD: 15.06

How much of an extreme spread do ya'll usually consider too much?

I'm really liking the Longshot load since it fills the case but not so much that I have to advance the shellplate on my 650 super slowly to avoid powder spillage like with 4756. I need to work some more up with 7625 but at 7.5grains I'm starting to see the primers flatten out a little bit. I'm not sure how much further I should push that one. Does anyone have a picture of how flat a primer is too flat?

Thanks,

Trodrig

[Kingman]

I was running 8.1 of longshot with 115's. You gotta be careful at that point and watch the chrono readings, if you are getting over 50 fps es on that powder you are nearing danger zone.

[DJPoLo]

trodrig, I know you've already done a bunch of work with 115 grain bullets but you could also try getting some 121s or 124s. It will take less powder to make major and I doubt you'd tell the difference when shooting.

Just a thought...

-Chet

[joecichlid]

I am all about the Longshot. I run 7.6 grains under a 124 grain bullet in my Open gun. No extra holes though, just a 4 chamber/8 port comp.

Joe W.

[trodrig]

Thanks for the info guys! I'm hoping to be able to shoot a hundred rounds of each powder this coming weekend and decide which one I like the feel of best. If it turns out that I like 4756 best, I think I will do as Chet suggests and try the 121 or 124 grain bullet to cut down on the spillage! I'll keep an eye on the ES with Longshot too. If I go with that one, I was thinking I might need to bump it up a little bit for some extra margin over the 165pf floor. I'll need to shoot some hot/cold rounds to see the effects of temperature. Does anyone know if any of these powders are temperature sensitive? If so, is it a positive or negative temp coefficient?

When testing different loads side by side, do ya'll simply run bill drills and see which one allows you to track the dot best?

Thanks,

Trodrig

[CenTX]

4756 can vary a lot from batch to batch. Anytime you change batch numbers with 4756, youshould check your loads.

[XRe]

Any change in powder lot, you should rechrono, regardless of powder type I've had interesting changes in VV powders occasionally, too....

As far as testing goes, I've done a variety of things. Subjective feel, various drills - bill drills at different ranges, index drills, shoot on the move drills, etc. I narrowed down to a few working loads from there, and then compared in matches, etc, too. Since you're new to Open, your best bet is to find one load that works, and shoot that for several thousand rounds, and just get used to how the gun works and moves. Then you'll have a base of information to work from in doing comparisons... Right now, everything is so foreign that you're really just making a wild guess between things...

[Kingman]

I really liked longshot in the super. I am going back to trying it again in a 9mm case this time.