Lake City Brass and the Like


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Vacek
July 9, 2011, 12:18 AM
OK, understanding fully well the LC brass is thicker and therefore there is less volume; and agreeing that less powder should be used for a given load, I have a question. Actually 3.

First, what is the basis for the "reduce the published load by 10%"? That seems kinda arbitrary. Is there any real science backing the 10% number up; or a value published at one point in time and has now become unquestioned law?

Second, Let's say that a load for 308 Winchester calls for 44 grains of Varget behind a 150 grain bullet and there is a publshed velocity of X. If I then use 40 grains in a LC Brass (thus obeying the law of 10%) will the pressure and velocity still be in that particular published range +/-?

Thirdly, does military match brass also have reduced volume and is the match brass of better overall quality?

Curious minds want to know.

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Waldog
July 9, 2011, 01:14 AM
1. 10% reduction has been the standard since smokeless powder was invented. Why 10%?. Because it works. You should never use a HUGE reduced charge, like 50% with rilfe powder. There is a is rare posibilty of detonation that will blow up your gun.

2. Velocity listed in loading manuals is acheived in a labratory enviroment with a TEST barrel with pressure sensors. It could be a 30" barrel or a 20" barrel. You just don't know. The velocity they acheive could +/- 300 to 500 fps different. The point is; your rifle is signficantly differnt than the LAB test gun. Velocity is dependant up the "internal ballistics" (From ignition to the bullet leaving the barrel) of your rifle. The only way for YOU to know your velocity is to use a chrongraph. You can get good one for less than $100.

3. LC MATCH is premium brass. It is thicker than standard brass and is VERY CONSISTENT. Plus the primer pockets are not crimped! Standard LC brass with crimped primers is OK. Nintey Nine percent of it was fired in a machine gun. This really stretches the brass and case life is short.

bfoosh006
July 9, 2011, 02:41 AM
Simple answer.... no two barrels are alike. One may have a shorter throat, which has the bullet just kissing the lands, which most milspec barrels have a more generous leade ( 5.56 v. .223 )...
to many possible differences to list.... ( rifling type, actual bore diameter, bullet construction... solid copper )

And now for your reading pleasure....

http://www.leverguns.com/articles/ballisticians.htm

"Dear Ballistician: Your reloading manual is all wrong! You say on page 713 that 11.2 grains of Super-Duper powder will push the 125 grain bullet at 1468 fps. My barrel length is the same as yours, but when I tried this load and had my friend chronograph it the velocity was only 1411 fps. Why are you so far off?"



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Letters like this imaginary one are all too common. In an effort to pinpoint one reason for such velocity differences, the Speer Ballistic Laboratory selected three lots of .357 Magnum ammunition in different bullet weights. These particular lots of ammunition were selected because of their uniformity, not because of high velocity. The ammunition was fired in all of the .357 Magnum guns available to the lab at the time.

The different handguns were all tested in same manner with the gun muzzle elevated and then gently lowered to the horizontal for each shot. Every effort was made to make the results as accurate as possible.

The table shows the average velocities of the three different bullet weights in each of the guns tested. Note that in the standard 10" test barrel, made to tight ammunition industry specifications, the extreme variation (EV) in the velocities ranged from 48 fps for the 125 grain hollow point bullet, to 38 fps for the 158 grain soft point bullet. Using the 6" barreled revolvers as an example, the EV between all 125 grain bullets fired in all the 6" barrels was 376 fps, almost 8 times the EV in the test barrel. The EV for all 6" barreled revolvers with the 140 grain hollow point ammunition as 275 fps, over 10 times the EV in the test barrel. The 158 grain soft point ammunition showed an EV of 282 fps, almost seven times the test barrel EV of 38 fps.

These large variations are due partly to the relatively very small differences in chamber, bore, forcing cone rifling, and barrel-cylinder gap dimensions and in the finish or smoothness of these interior surfaces. Chambers will vary minutely even though cut with the same reamer, as will all other machined surfaces. It is virtually impossible to manufacture two of some machined metal item, even as simple as a revolver, with all dimensions and finishes exactly the same. When hundreds of thousands of .357 Magnum revolvers have been made by thousands of different people, in different factories, with different materials and tooling, it cannot be surprising that there are differences between guns.

These minor differences between guns cause some of the differences in ballistic measurements. Additional variations, due to differences between different makes or lots of bullets, powder, primers and cases, powder charges, loading dies, loading techniques and chronographs complicate the problem. Many times these small differences tend to cancel each other, but when everything goes one way, the resulting variation may be relatively large.

These velocity tests are not presented with any idea of claiming that one particular brand or model of revolver is superior to another. A repeat of the test with different ammunition might well reverse the relative standings shown here. The point we want to make is that even with the very best quality ammunition available, there will always be velocity variations when the ammunition is fired in a different gun.


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Gun Description Barrel
Length
-Ammunition Used in Test-

125 grain
140 grain
158 grain
S&W M19#1 2.50" 1190 1132 1034
Colt Python 2.50" 1205 118 989
S&W M19#2 2.50" 1209 1118 1018
Ruger Security Six 2.75" 1233 1154 1075
Colt Trooper Mark III 4.00" 1317 1175 1101
S&W M66 4.00" 1385 1225 1117
S&W M19#1 4.00" 1368 1227 1153
S&W M19#2 4.00" 1374 1242 1146
Ruger Security Six #1 4.00" 1370 1242 1130
Ruger Security Six #2 4.00" 1380 1267 1151
Dan Wesson 4.00" 1358 1280 1160
Ruger Blackhawk #1 4.625" 1361 1266 1159
Ruger Blackhawk #2 4.625" 1480 1336 1196
Ruger Security Six #3 6.00" 1436 1311 1210
S&W M19 #1 6.00" 1400 1282 1179
S&W M19 #2 6.00" 1372 1281 1154
S&W M19 #3 6.00" 1603 1417 1284
S&W M28 #1 6.00" 1307 1246 1080
S&W M28 #2 6.00" 1499 1364 1207
S&W M27 6.00" 1547 1358 1248
Colt Python #1 6.00" 1227 1142 1002
Colt Python #2 6.00" 1477 1373 1251
Colt Python #3 6.00" 1468 1364 1207
Ruger Blackhawk (new) 6.50" 1471 1375 1262
S&W M27 8.375" 1547 1358 1248
Ruger Blackhawk 10.00" 1738 1544 1365
T/C Contender 10.00" 1944 1726 1587
Martini Rifle 17.375" 2121 1906 1678
Winchester 92 Rifle 20.00 2153 1964 1824
Marlin 1894 Rifle 24.00" 2212 1994 1835
Velocity Test Barrel 10.00" 1866 1732 1591

Velocity Test Barrel Extreme
Variation
48 26 38




Note the difference in velocity for some of the identical makes and models..... In particular the 3 S&W M19s

kingmt
July 9, 2011, 03:22 AM
10% reduction is from the max load. You have different variables. If you are fallowing a manual that list a starting load you are probably OK starting there. You will not blow up a gun with a 50% reduced load but the next round might. it's not likely your will get close to the same speed if your load is 4gr under theirs.

I don't have a answer about the volume.

EddieNFL
July 9, 2011, 08:05 AM
OK, understanding fully well the LC brass is thicker and therefore there is less volume

You may want to measure your specific lot. It may be true...or not. I have hundreds of pounds of LC 7.62 and 5.56 covering several decades. With a few exceptions it is never the heaviest. Some civilian headstamps are lighter, some heavier and some the same. Seems the older headstamps are the heaviest.

USSR
July 9, 2011, 09:17 AM
Thirdly, does military match brass also have reduced volume and is the match brass of better overall quality?

I will respectfully disagree with Waldog. LC Match brass is far from premium brass. You may PAY a premium for it, but as far as consistency and accuracy typically produced by it, most commercial brass will exceed it. The volume is the same as standard military brass. If you want premium brass, then buy Lapua brass.

Don

Obsidian
July 9, 2011, 02:14 PM
I agree with the measuring your lot's case volume. I'm not sure where it is off hand but there are charts measuring LC brass weights vs civilian weights and the total volume. I can attest that my 5.56 brass LC headstamp actually has a -greater- volume than civilian brass and still holds up much better to reloads. However I also have some British brass that has a reduced capacity to civilian brass. In short you have to see and do your own measurements for each lot.

Vacek
July 9, 2011, 02:17 PM
You all are missing the point. Here it is.

Same gun... my 308 Weather Warrior. Two pieces of Brass, 1 is LC and 1 is R-P. Now according to lore the LC brass will product more pressure for 42 g of Varget than 42 g of Varget in the R-P. OK, I believe that, the volume of my LC Brass is indeed less.

So here is the question and this is hypothetical but hopefully will get to the point. Lets say that 42 grains Varget is loaded in the R-P and 37.8 g of Varget (that's the 10% reduction) is loaded into the LC all behind a 150 g bullet. Would I expect similar pressure and velocity for both? I am not looking for exact here just trying to understand. Yes, I will get a chrono sometime, but right now its just a question.

higgite
July 9, 2011, 03:20 PM
So here is the question and this is hypothetical but hopefully will get to the point. Lets say that 42 grains Varget is loaded in the R-P and 37.8 g of Varget (that's the 10% reduction) is loaded into the LC all behind a 150 g bullet. Would I expect similar pressure and velocity for both?

For you QuickLoad users out there.... Is that an appropriate question for QuickLoad?

USSR
July 9, 2011, 04:15 PM
So here is the question and this is hypothetical but hopefully will get to the point. Lets say that 42 grains Varget is loaded in the R-P and 37.8 g of Varget (that's the 10% reduction) is loaded into the LC all behind a 150 g bullet. Would I expect similar pressure and velocity for both? I am not looking for exact here just trying to understand. Yes, I will get a chrono sometime, but right now its just a question.

Vacek,

The answer is no. There is nowhere's near a 10% difference in case capacity. While I don't use Varget (I use IMR4895), I would anticipate an approximate 1.5 - 2.0 grain difference, depending upon the brand of commercial brass used (I don't use R-P).

Don

Waldog
July 9, 2011, 04:56 PM
Vacek,

The answer is no. There is nowhere's near a 10% difference in case capacity. While I don't use Varget (I use IMR4895), I would anticipate an approximate 1.5 - 2.0 grain difference, depending upon the brand of commercial brass used (I don't use R-P).

Don

USSR nailed it!

I would also agree on the LAPUA brass. It is, by far, the best. I still prefer LC MATCH over your run-of-the-mill WIN, FED, REM, etc.

Hondo 60
July 10, 2011, 01:03 AM
There is nowhere's near a 10% difference in case capacity.

That's correct. Infact I don't think there's a pat any % difference.
Each case maker has their own ideas.
If you're looking for ultra-consistency, you'll need to separate your brass by headstamp
and work up each one separately.

Or you can say "to heck with it", & just work up one load that is "close enough"

CaneCorso85
July 10, 2011, 02:04 AM
3: There is no difference between LC Match and LC, save the headstamp and the the ridge around the outside, which is for round identification in low light situations. Physically the two are exactly the same.

P-32
July 11, 2011, 02:46 AM
The deal with Lake City brass being heavuer than Comm Brass totaly has to do with the lot number for 223 brass. There is some L/C 5.56 which is about the same weight as Winchester brass. Federal brass has proven to be one of the heavest and the most worthless.

For &.62 Nato and '06 ss GI brass then generaly you should reduce a couple of grains when starting out because generaly they are heavier than comm brass. .

USSR
July 11, 2011, 08:23 AM
There is no difference between LC Match and LC, save the headstamp and the the ridge around the outside, which is for round identification in low light situations.

The only LC Match ammo that had a cannelure on the brass was M852, which was to denote that it was not to be used in combat. All LC M118 Match and M118 LR do not have the cannelure.

For &.62 Nato and '06 ss GI brass then generaly you should reduce a couple of grains when starting out because generaly they are heavier than comm brass.

While this is true with 7.62x51/.308, it is generally not true with .30-06. Commercial Federal .30-06 is actually heavier than USGI .30-06 brass.

Don

velocette
July 11, 2011, 10:04 AM
In my tests, commercial 308 Federal brass has been heavier than LC or any other brand of brass, military or commercial. Just incidentally, Hornady and Winchester brass have been the lightest and RP makes up the middle ground.

Roger

Maj Dad
July 11, 2011, 01:48 PM
Since we're on the LC subject, recently I bought 500 once-fired LC brass (fired in AR-type rifles, not MGs), and included were 20 LC Match, and a similar number of brass marked "LC 06" on top, and "LR" on the bottom. My OTW guess was long range, but I have never encountered it before. There were a few different years, not only 06.

Anybody?

USSR
July 11, 2011, 03:01 PM
recently I bought 500 once-fired LC brass (fired in AR-type rifles, not MGs), and included were 20 LC Match, and a similar number of brass marked "LC 06" on top, and "LR" on the bottom. My OTW guess was long range, but I have never encountered it before.

Current issue sniper ammo as of 10/01/97 and called M118 LR. And, you are correct, the "LR" stands for Long Range. It uses the then new Sierra 175gr MatchKing bullet, which was developed expressly for this round.

Don

bigedp51
July 11, 2011, 03:17 PM
Vacek

At the Lake City Army ammunition plant Remington produced ammunition there until 1985 when Winchester won the contract. In 2001 Winchester lost the contract to Alliant Techsystems Inc. (CCI/Speer)

So remember your LC cartridge cases are made by the cheapest bidder in a ever changing global economy with shifts in ownership and stockholder greed.

The following data is from 1974 and was compiled by Ken Waters and was used with the Powley Pocket computer for handloaders.

.308 Winchester case weight in grains
Rem-172.9
Win-155.4
Gov-186.4

.308 Winchester case capacity in grains of water
Rem-50.1
Win-51.2
Gov-47.9

Every production run of cartridge cases will be different weight and internal volume by each manufacture and will vary.

The popularity Lake City brass deals with it being thicker in the base web area and its ability to withstand the larger military chambers and longer headspace. When you have cheaper brass that can be reloaded many more times than commercial cartridge cases LC brass becomes popular.

When you compare reloading manuals, cartridge cases, bullets and powder there is always a wide variation in data. If you keep written records with cartridge and bullet data you can safely start loads from mid to upper mid range load data.

When starting on uncharted ground I start with the lowest average load in the manuals and work up reading the primers. I can say you will never know what your working with unless you weight the cases. The other night I was weighing .223/5.56 cases and the commercial Federal case were the heaviest, and the military cases were the same average weight as Remington.

Bottom line start low and work up and you wont have any surprises when you pull the trigger.

http://i122.photobucket.com/albums/o254/bigedp51/powley-3.jpg

Dated 1978 Handloaders Digest eighth edition. Weigh your cases and see if things have changed in 37 years. :eek:

http://i122.photobucket.com/albums/o254/bigedp51/casecapacity.jpg

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