How to read signs of overpressure... 38 SC

[SamboSon]

I had my first outing today with the 38 short colt and 160 billy bullets. The highest charged load today was chrono'ing in the 750-765 range. The primers got progressively flatter looking from my starting load to my max load, but they all ejected with ease. What will a federal primer look like on the edge of overpressure? I hear federal primers aren't a good way to assess pressure because they always end up looking flat because they are so soft. What power factor should I shoot for? 125-130? I am not familiar with how they verify loads. Do all rounds have to be over PF? Will one slow bullet disqualify me?

Thanks, Sam

[Bubber]

Are we talking ICORE or USPSA. The process differs. In ICORE they will shoot until one round makes 120 pf and then you are good to go but you will only get 6 chances from the ammo collected A 7th round may be collected to weigh the bullet. In USPSA it an average of 3 rounds fired over the chrony and that is a 125 pf. If not made after the first three rounds, they will fire another three. If that does not make it they will use the best three of the 6 for an average. If it still does not make it the last round collected may be weighed or shot over the chrony, your choice. And looking at the primers is not a good indication of high pressures. If the empty brass comes out easily you are good to go. Happy hunting. later rdd

[SamboSon]

Thanks Bubber! The load I am developing is for icore. That sure is a lenient way they test for PF. I just bumped the load up a tenth, and that should get me a consistent 125 PF. Now for accuracy testing... What kind of extreme spread do you consider acceptable? It started to rain today while I was testing, so I was only able to get off 3 rounds of my heaviest load. The 3 were 756, 773 and 768 I think. I just loaded up 50 more with various crimps and 10 with a tenth more powder.

Edited August 22, 2013 by SamboSon

[DougCarden]

Sticky extraction is what you want to watch for.....I recommend loading 10 over your PF needed.....due to varying ...um....chrono set ups at matches....

Experiment with your crimp as well. More may make the load more consistent and tighten up your groups as well.....

DougC

[Bubber]

17 fps is a great extreme spread. I shoot 8 over a chrony to get a good comparison and then my chrono will give me a standard deviation. Be sure every once in a while you weigh your bullets. If you go with a 125 for ICORE it will make a slight difference but if you are close that could spell trouble. But once you are in the ballpark, load for accuracy. And +1 to Doug's comments Later rdd

Edited August 22, 2013 by Bubber

[SamboSon]

Just got back from shooting the 50 rounds I loaded last night. I am a little closer but not quite there. The fastest load from yesterday ended up averaging right at 120pf with an extreme spread of 34. Out of the 10 from the bumped up load 6 were in the 770's, but the last 2 got weird. One was 742 and the next was 794; extreme spread of 52. I am just below 124 power factor, so I guess I will work my way up to 130 a tenth at a time. I think .2 more grains will make it. I am going to try to tighten up the crimp and see if the extreme spread tightens up.

[Toolguy]

You really want to be around 130 PF. At 800 + FPS you will be in the right range. If your SD is less than 50 you are doing fine. Usually group size and SD are better at 130 PF or higher. Sometimes you can have an accurate load with a high SD, but a lower number is more desirable.

[toothguy]

http://www.brianenos.com/forums/index.php?showtopic=177186

[Hi-Power Jack]

What power factor should I shoot for?

Sam, I usually fire 20 shots over a chrono and look at the LOWEST

velocity. That should be PF125, or a little over.

[S&WIowegan]

I have been running Billy Bullets in my 627s for at least 4 yrs. now. The Federal primers seem to always flatten with minor loads. One thing you should look for is bullet jump. Stop after firing 4 rounds and look for jump. If none, then check after 6 rounds next. Experiment with crimp to minimize jump because the pressure drops as bullets move out. If pressure goes down enough velocity may drop enough to change trajectory(might be a problem on 50 yd. standards).

Bob

IA203

[pskys2]

I'm playing with 158 Berry's and 160 Bayou's and notice a sharp increase in velocity with just .1 grain of powder. I'm sure the pressures are way low and then .1 more and they go to normal, everything settles down but the velocity jumps up to the 860's and a pf of 135+. I'm using WST mostly at this time and some Ramshot Competition, really liked the loads I had with Titegroup, but don't have enough on hand for all others.

A couple of loads I started with actually hit 140+ PF with no pressure signs.

Remember you're using this in a 357 mag, the only weak point is the case.

What powder are you using?

[SamboSon]

I purposely left out the powder I am using because I didn't want the thread to turn into a "use a different powder" discussion. I am actually using bullseye. I realize it is a fast burning powder that is known to be very dirty, but it is what I have at the moment. I find bullseye to be sooty but burns completely and doesn't seem to ever get thick. I have shot thousands of rounds in 38 special and have not had any problems with soot building up under the ratchet or any other places that I have read about. I just wanted to test the waters with short colt and see if it is something I want to pursue. I am shooting them out of an old k frame and plan to buy a 627 if I can ever find one.

[pskys2]

I have some old Bullseye still. But haven't tried it yet. In these times you have to use what you have.

I don't know as if there is a "most" popular powder as in Clays for .45acp.

[SamboSon]

Just got back from my third outing with the short colt and am quite satisfied. I had a 50 shot avg of 797.4 fps, 46 ES and 13 SD. I have no point of reference compared to other SC loads but recoil is fairly soft. I have not weighed the charge(scale is on the fritz) but with a lee auto disk pro, the charge is supposed to be 3.5 grains of bullseye.

I originally purchased the starline short colts but was unhappy with the bulge I was getting when seating to where I wanted. I had to seat the bullet all the way out to 1.18" to have zero bulge. At 1.18" I was crimping right into the middle of the top driving band, and I felt that I would ideally like to crimp right at the point where the bullet begins to taper. It just wasn't possible to do this with starline brass without causing any bullet deformation. At 1.115", the bullets were being reduced in diameter at the bottom driving band and the bulge was extreme. I cut down 4 different brands of brass to .760" and measured the wall thickness. I believe they were remington, winchester, pmc and federal. The only brass that would allow the bullet to be seated to 1.115", where the bullet begins to taper, was federal. I was surprised that the non-starline hearthco brass from tk custom holds federal brass just as tight and precise, maybe even tighter, as the hearthco/starline combination. I know many people are achieving great accuracy with starline brass seated from 1.2" all the way to 1.13", but I feel that you cannot maintain a completely unaltered bearing surface on the 160 billy bullet without seat to below 1.13". I am using a tight roll crimp based on the advise of others and don't like the way the crimp deforms the bearing surface of bullet. Do any of the "problems" I have mentioned matter? I honestly don't know, but I feel that taking every effort to preserve the original state and dimensions of the bullet can't hurt.

So far the 38 SC experience has been enjoyable, and I feel comfortable enough with the loading that I am pretty sure I want to pursue ICORE limited. Now to find a 627.... that's going to be the hard part!

[SamboSon]

Before you comment, the bullets are not actually billy bullets. They come from the same bullet mold and are traditionally lubed with a light coat of molly. I ordered them from black and blue bullets. They are very affordable. The bullets did not cause any leading whatsoever. I honestly forgot to even pay attention to how much smoke they created. I was way too busy staring at the the chrono.

Anyway... I posted these pictures to explain my seating depth and crimping issues. from left to right:

1: This bullet is seated to 1.13", the point where the top of the brass meets the very end of the bearing surface. If you compare to the unaltered bullet immediately to the right you can see two things: 1, the roll crimped reduced the diameter of the bullet at the very top of the bearing surface resulting in a setback of the bearing surface. 2, the bottom driving band has been swaged or reduced in diameter because of the drastic increase in wall thickness of the starline brass.

2: Unaltered bullet showing bearing surface.

3: This bullet was seated to 1.115 in federal brass and crimped with a heavy roll crimp. You can see that the bearing surface was not altered in any way, even with an extreme roll crimp.

4: This bullet was seated, crimped, re-seated, re-crimped a few times. Focus on the line in the middle of the top driving band. The bullet was seated to 1.18" to avoid any bulge in starline brass and was lightly roll crimped. Even a light roll crimp deforms the bearing surface (the line in the middle of the top driving band)

Am I being too critical and obsessing over this whole thing? Maybe! Probably! I may have OCD

If anyone is wondering... I used the sharp edge of the caliper jaws and rotated the bullets to scrape off the moly coat.

Also, I obviously don't have a bullet puller. Don't criticize!

Edited August 23, 2013 by SamboSon

[scottyinAZ]

nothing wrong with tinkering with your hobby!! enjoy

[Shadowrider]

I never use a roll crimp unless I have a cannelure to crimp into or a shoulder that I can crimp over. A conventional taper crimp die is what I use in all other instances.

[pskys2]

Yes and No. The bulge may cause the rounds to not fall easily into the chamber on reloading. If that isn't happening then as long as they don't keyhole and accuracy is good then go for it.

I usually play with different lengths, crimp types and crimp diameter trying to find the most accurate loads.