Chrono Results W/lead And Copper-coated Bullets

[bernmart]

I showed up at the range today with two loads identical except for the bullets: 4.6 gr. Titegroup, Winchester LP primers, etc. Only the bullets were different: 230 gr. moly-coated Bear Creek LRN, and recently acquired 230 RN Rainier Copper-coated.

Both fed perfectly, shot equally accurately. Down the line from me was a guy with a chrono set up, and he offered to shoot magazines of each kind of round through the chrono.

Big surprise! The Bear Creeks averaged almost 100 fps faster than the Rainiers--840 v 746 average velocity through the chrono. Also, the Bear Creeks were very consistent--std dev. of 2, while the Rainiers were as much as 60 fps apart in a 7 rd magazine.

I've never had my loads shot through a chrono before (this guy only shows up during the week when the range is quiet, and I had a rare weekday off), but from what I've read these are pretty extreme differences for bullets of equal weight and contour.

I'd appreciate comments, perspectives, advice?

Thanks, Bernie

[Gun Geek]

The velocity difference is not that big of a surprise. Lead bullets are almost always faster than copper (plated or jacketed), lead is a better lubricant, and probably also melts a little at the temp and pressures to which we subject it.

The surprise is in the variability of the plated bullets. I have messed with coated and plated bullets and fast powders and sometimes they don't work well together. I think fast powders blow the plating/coating off the bullet more than slower powders. This might explain the variability.

Crimp is also critical on plated bullets. With most crimp dies, crimp is affected by case length (longer cases get crimped more), so some of what you saw could be from using mixed brass and the resulting crimp issues. You might try using the same headstamp and (god help you) trimming the cases, and being very careful on how the crimp die is set. Then see if the SD goes down.

[BSeevers]

No Surprise

Lead always has higher pressures hence higher velocities. Always chrono your loads.

[robomanusa]

your load is about identical to the load I use in my 5" SW625. I use zero 230gr Jacketed RN w/ 4.6gr titegroup at 1.260 OAL. velocity varies maybe 20fps or so with a 741fps average. All my 45acp loads are with winchester brass, so Id say your inconsistency is with the crimp that tends to vary with mixed brass.

[bernmart]

OK; I get that lead bullets go faster than jacketed or plated, all things being equal. Assuming that the crimp is the culprit behind the velocity spread among the plated rounds, how explain the extreme consistency among the Bear Creeks? In any case, thanks for all the responses.

[robomanusa]

Off the top of my head, my guess is that you had more of the same brass you tested loaded into one brand of brass for lead than you did the plated ones for testing, might also be that since lead bullets are .001 or so larger they provided a more consistent crimp than did the plated ones.

[grumpy_m]

I don't have an answer, but I do know that my experience has been that I can consistently get a reasonable velocity spread with hard-cast 45 200gn SWC lead bullets and mixed brass usually like +- 1 in power factor. I have done that for years (from 1995-2002), match after match, never a problem. With lead (never made a difference with manufacture as long as it was hard-cast), I have used WW231, Bullseye, Unique, WSF, WST and Titegroup and only CCI large pistol primers. My last year or two of using lead in competition was a combination National bullets, Titegroup and CCI primers and mixed range-brass exclusively and again never a problem.

I switched to plated 200's (you can pick a flavor form West Coast or Berry's, it didn't matter) and I now hold my breath at every match where there will be a chrono. I have always made the minimum, but the spread is very disturbing. I can remember the power factors ranging form 160 to 170 or so. I have tried tighter crimps and that appears to help some. I also get the same results when making test loads to chrono myself.

Now when I use 9mm plated bullets with Titegroup and mixed brass the problem is non-existent.

So what i have learned over the last year or so reading and searching for an answer on this forum and others is that the hard-cast lead bullets for a .45 are probably the easiest to reload for consistent results for what ever reason. The use of soft lead in plated bullets has caused other issues for me as well (mostly my fault) that were not a factor with the hard-cast. So if you can find a definitive answer I would be glad to hear the solution.

For me, I am going to try a jacketed 200gn projectile in .45 and continue to shoot up the rest as practice ammo.

[AzShooter]

I have never had luck with Coated bullets. The coated jackets will split off the bullet and you will even find pieces of the jacket in the target when you shoot close.

Regular jacketed bullets have never shown this problem. The jacket's stay in tact If you must use jacketed spend the extra money.

[Garrett]

I tried some of the moly coated lead stuff a while back. It ran just fine, and accuracy was acceptable. But it left a weird residue in the comp that is pretty tough to scrape out. Don't seem to have problems in a non-comped gun though.

[Harmon]

No Surprise

Lead always has higher pressures hence higher velocities. Always chrono your loads.

<{POST_SNAPBACK}>

anyone correct me if im wrong, but i discussed this with the ballistic lab at Accurate Arms a few years ago,

Lead bullets will give higher velocity and LESS chamber pressure because its easier to push a cast lead bullet down the bore than it is a jacketed bullet.

compare lead bullet loads that show pressure and velocity along with the powder charge and youll see what im talking about.

you should see more velocity, less powder or less pressure...or all three.

as far as the titegroup load goes, i dont need anywhere near that much with a 230 grain lead bullet to make the power factor...the same load i use with 230 plated gets a 230 lead and both make the major power factor w/o any trouble.

[BSeevers]

Hmm Makes sense. As you all know lead increases velocity with same load. I was always told increased pressure too but that makes sense. We know not why but know it to be sure.

I was told lead seals faster and more to the barrel to increase pressure. Heck its usually .001 bigger anyways.

[Canuck-IL]

I recently had an opportunity to use a chrono and try out some Vectan Ba-10 with Rainier 230RN...thought the sd was surprisingly small

OAL 1.255 Ba-10 gr

RN Plated 230 3.2 3.4 3.5 3.8 WWB

Mean 710 728 732 778 857

SD 5.2 3.9 5.2 5.5 13.7

Win White box is the last column in the spreadsheet above

/Bryan

[Canuck-IL]

damn! in the preview, the columns were squarely aligned ... is there a trick here??

/B

[shred]

use the 'code' tag. It's a monospaced font

Code 12345
line  234

You can also select 'Courier' from the Font menu, but note multiple spaces get eaten so it's trickier.

Courier Font Mode 1 3 5

Line 2 .......... 2 4 6

[Canuck-IL]

Thanks!

/B