case weight variation

A

Aussie steve

New member
I am having a .17/.223 built at the moment, the rifle is a rem 700 which will be fully trued, fitted with a 27" Lilja heavy contour barrel, and bedded into a rem laminated varmint stock. The trigger has already been worked over to about 10 oz, and I am going to mount a Leupold VX3 6.5-20x40 on it in hillver mounts, and plan on shooting either the 25 Vmax or Berger hp.

I hope to have a real shooter with this set up, and so out of curiosity I weighed 60 out of 200 rem nickel .223 cases I have to form, and they all weigh within 1.5 grains. I have never bothered with weighing cases before, so now I am wondering if thats too much variation and would I be better batching the cases based on weight? If so, how much additional accuracy is it possible to extract?

Cheers

Steve
 
mistake # 1,,,,,,,, nickel case's,,,,,, I've never had any luck with them,,,,too hard,,,,, I usually weigh to within one grain to save time ,,,,,,,,, I always weigh after all prep work is finished, including triming length

the wind is my friend,,,,,,,,,,,,,,,,,,,,

DD
 
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david dumas said:
mistake # 1,,,,,,,, nickel case's,,,,,, I've never had any luck with them,,,,too hard,,,,, I usually weigh to within one grain to save time ,,,,,,,,, I always weigh after all prep work is finished, including triming length

the wind is my friend,,,,,,,,,,,,,,,,,,,,

DD
Click to expand...

Yes......... Hard on dies and chamber.... But if this is what ya got....


Don't get to fixed on case weight...... The wind........ YES.... .17's get blown aroud real easy!

cale
 
Thanks guys for the help, I dont overly like nickle brass myself, but at night it can be easy to confuse a .204 with a .17/223 or a .222, so I went the nickle option just to aid in keeping the right ammo in the right gun.

Steve
 
If you got a + or - 1.5grs on the brass, I wouldnt worry about it. I have seen alot worse results.

Good Luck

DR
 
Sorry, to disagree, but I would not shoot 1.5 gr difference in my 6.5-284. in a smaller case and an even smaller weight bullet little differences are big.
 
Get your brass from Lapua, put the scales away. If I had mixed lots of brass, then I would check few, then put the scales away. I feel this case weight thingy is way over blown. But just stay with Lapua. Toss the nickel cases, there in lies trouble.
 
Weights

Do you really think you would be able to ascertain any difference on the target in anything except a true Benchrest Rifle??????..........jackie
 
When a gun is fired the brass expands to fit the chamber. Brass is about 8 times denser than water, so when you fire the gun a 1.5 grain difference in the weight of the brass will make about a 0.2 grain H20 difference in the chamber volume unless of course the extra weigh is around the extractor groove where it may not expand.

I just ran the numbers using Quickload. A 0.2 grain H2O reduction in case volume on a 17 Rem (similar to 17-223) shooting 25 grain jacketed bullets at 4000 fps will cause a predicted 15 fps velocity increase.

For comparison a 0.1 grain increase in powder weight makes an 18 fps increase in velocity at 4000 fps.

So if you bother to weigh each charge to better than 0.1 grains then you probably should also sort your cases by weight if you're tying to achieve the best precision (lowest extreme velocity spread).

You may find it interesting that a 0.1 grain change in bullet weight (25.0 to 25.1) only decreases the velocity by 2 fps. There are some loads which are nearly neutral to bullet weight versus velocity since the heavier bullet causes the chamber pressure to increase.

For this example I used a 24" barrel, plain Berger bullet, and 21.1 grains of IMR 3031 to give the predicted 4000 fps. It's not a hot load, around 50kpsi.
I use it in my 17 Rem AR-15. I do weigh each charge a little better than .1 grain but I don't sort the brass.
 
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Aussie steve: You are a man after my own heart!
Some years ago I had a full custom Varmint Rifle built in caliber 17 MachIV on a Remington 700 action.
It was going to have a 26 1/2" Lilja barrel fitted to it.
Unfortunately the Lilja folks had shut down their 17 caliber barrel making for a time and I had to re-order a barrel through the fine folks at Shilen.
My barrel is also heavy of contour and is 26 1/2" long - recoil is NOT a problem with this wonderful shooting Rifle!
Using "un-sorted" Remington 221 Fireball brass I obtain excellent accuracy with this Rifle!
As an example the last four groups (5 shots at 100 yards) I fired with this Rifle measured .264", .339", .322" and .262"!
These groups were all fired in different years by the way and were pre-Hunt sight in verifications.
This Rifle had a Leupold 8.5x25 variable on it while shooting those groups by the way.
I use the wonderful Berger 25 grain M.E.F. bullets in my 17 MachIV.
As for nickel plated brass I have been using it (a lot of IT, and in MANY different calibers) in my handloads for 3+ decades!
I have NEVER encountered even a single negative side effect from use of this type brass.
I actually prefer nickel plated brass for my Rifle loads in some regards.
Back when I used to sort my brass by weight I used to simply buy twice as much brass as I wanted to have on hand for a particular Rifle - I seperated the heaviest 25% of the brass and the lightest 25% of the brass and sold those while they were still new unfired.
I think it may have helped a bit accuracy wise.
Some time back I quit sorting brass by weight in my Varmint type accuracy Rifles.
I don't think 1.5 grains total brass weight variation will make much difference at all in your accuracy.
I have no proof for that to exhibit for you right now though.
I had my Oehler chronograph to the range some years ago and my close friend wanted to run his pre-64 Winchester Model 70's loads over it.
The Rifle was in caliber 270 Winchester.
He was shooting Nosler 130 grain Ballistic Tips in his VERY accurate handloads.
That number sticks in my memory as his chronographed load that day had an extreme velocity spread, coincidentally, of 130 F.P.S.
AND, the group (5 shots at 100 yards) my friend shot that day measured just at .500"!
For moderate ranges I don't let larger extreme spreads in velocity overly concern me anymore.
If your initial load testing does not fulfill your accuracy needs then do go through the time and effort to sort your brass by weight.
Best of luck with your 17/223!
Hold into the wind
VarmintGuy
 
IMO, the best thing to do would be to weigh and group the cases, then test it to see if there is a difference. Develop a load with the heavy cases, then try it in the light ones and see what happens. Try mixing up some cases of different weights and fire some groups.

I weighed 2 lots of Lapua .223 brass and had a difference of .9grs, however one lot was heavier than the other, and each lot only had a spread of .5grs within that lot. I then took a heavy and a light cases and filled them with ball powder to see what the actual capacity difference was. It turned out that for every .3grs in the case, there was a difference of .1gr of powder. I did this with enough cases of different weights to check it and it was repeatable.

I haven't tested it myself, so I don't know if there is any difference for certain, but I feel that the more variation you have the better the possibility that it could affect your groups.
 
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