Case Comparisons

[bumtownbutch]

What started out as a simple question, "How does LC brass compare to the old IMI brass?", soon turned into a major project. The biggest problem for me was to figure out a way to bisect the brass without loosing fingers as I did not have access to a machine shop.
With the help of TAJ45 (fellow Saubier member), I began collecting samples of 223 brass and other members of the 222/223 family. I cut the cases in half lengthwise and deburred them trying not to alter dimensions. I did not have a tube micrometer, but used my digital vernier caliper. I started at the rim of the case taking measurements of rim, web thickness, primer pocket/web thickness, head thickness, mid-length of the case, just behind the shoulder, and neck thickness. All measurements shown were taken from both sides, left and right, of the case-half and averaged. Here are the results:
PMC DAK
IMI LC 04 LC 05 LC 06 LC 07 LC 11 222 20T
Rim Tkn .043 .042 .041 .044 .041 .040 .042 .045
Web Tkn .1955 .188 .1875 .186 .1835 .187 .182 .175
Prmr Tkn .073 .066 .071 .073 .066 .066 .062 .055
Mid Tkn .0165 .014 .0155 .015 .016 .0135 .016 .015
Shdr Tkn .0135 .0105 .0115 .012 .0135 .0115 .015 .013
Nk Tkn .0125 .0105 .011 .011 .0115 .0105 .012 .012

Based on these measurements, I can understand why the IMI brass was so outstanding and able to withstand higher pressure loads before primer pockets expanded. But what really surprised me was the lack of web and primer hole thickness of the Dakota brand 20 Tac brass; I have been shooting it for years, but may start forming it from either LC 04 or LC 05 brass.
Draw any conclusion you like from my crude measurements. Enjoy. Great thanks to TAJ45.

[bumtownbutch]

My apologizes, I could not edit to put measurements and heading in correct columns. If you will PM email address, I send better looking results.

[Bill K]

Interesting.. I can not locate it again, but I recently read a article where a party compared/tested/measure the various main line brass case's. With all the bad mouthing Rem and others get, about crummy brass. Lapua was #1 and guess who was #2... Rem. That was interesting also. Anyone else read that article and recall where it was printed, what magazine, etc.? Bill K

[Tilleyman]

Case sectioning and measuring is always interesting... data driven research vs hearsay or assumptions often leads to some surprising results

Any chance of posting some pics of the different sectioned cases?

[bumtownbutch]

I bisect other samples of 223 brass. I found it interesting how WCC cases dimensions are so very close to the IMI dimensions.

TW WCC 09 WCC 10 Lapua 223
.041 .041 .041 .041 Rim thkn
.191 .198 .196 .168 Web thkn
.076 .080 .084 .050 Primer thkn
.043 .042 .044 .036 Head Wall thkn
.017 .0155 .013 .0155 Mid case thkn
.014 .015 .0105 .0135 Shldr thkn
.011 .0105 .0125 .011

[Lenard]

I have been impressed by LC brass for a couple years. I went thru those years of loading commercial brass and finally discovered that LC brass gave me the best groups with few fliers.

I formed several hundred of them for the 20 TAC and am extremely happy with the results. I had a small percentage that I culled for neck run out, but for the most part they are within .001. I cannot say the same for any of the commercial brass as run out is at least 20% from my experiences. And, I load them pretty warm.

[john]

Bill K: I think the article was in Handloader a couple or three months ago. I glanced at it for a moment of relief from supermarket shopping. I can remember being very surprised by the conclusions of the article. I don't think the article was convincing in terms of scientific process.

[bumtownbutch]

I goofed!!! The piece of brass I called "Lap 223" should be labeled "Dakota 223". I guess in my feeble mind, I took it for granted that Lapua and Dakota were the same; maybe or maybe not?????

[waynemac]

I'm with BTB on the brass issue. Via a good friend, I acquired 1500 rounds of AMU .556 ammo. It's loaded with Hornady 75 grain A-Max and new IMI cases.
It had been in an estate sale, and he picked it up with no good reason in mind. There was also several hundred rounds with Sierra 80 grain MKs in LC brass which was also new brass. The 80s had not been stored very well, and showed some tarnish, but the 75s looked good. I paid .10 a round for that, wish I could get some more. Although they are not magazine length, they work in my tactical .223 on a Rem. action with Wyatt bottom metal using Wyatt magazines. IMI brass is very good, strong brass. It has to be, those rounds make 3050 FPS out of my 26" barrel. Yep, .223/5.56 doing 3050 FPS with 75 grain bullets. I know that sounds crazy, but I've fired them over several crono graphs and they all agree. Primers are a little flat!
Wayne