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September 25th, 2008

.243 Winchester Brass Weight and Capacity Tested

Forum member Andy (aka GreyMist) has completed an interesting test, with five (5) different types of .243 Winchester Brass. He collected Federal, Lapua, Remington, and two different lots of Winchester-brand brass. Then he selected ten (10) cases at random from each brand and measured their weights. To ascertain case capacity, three (3) cases from each brand/lot that were closest to the average weight for that brand/lot were selected. The results were surprising: there was less than one (1) grain capacity difference between all the cases, even with a 14.7 grain maximum difference in case weight!

Measuring Procedures
The cases were sized in a Redding body die then primed with a spent primer. All were weighed before and after filling them with distilled water. The capacity shown is an average of all three (3) cases from that lot and represents grains of water. Note, I tested two lots of Winchester brass. Lot A was purchased in 1999. Lot B was from factory .243 ammo. There is a rather large disparity in case weight between the two lots. For more info and to see the weights of individual tested cases, visit GreyMist’s webpage.

Brand Federal Lapua Remington Winchester A Winchester B
Capacity 53.9 54.4 53.7 54.8 54.8
Aver. Weight 173.28 173.13 165.34 158.58 166.44
SD¹ 0.46 0.39 0.17 0.58 0.42
Range² 1.70 1.10 0.40 1.80 1.40
% of Avg.³ 0.98% 0.64% 0.24% 1.14% 0.84%

1) Standard Deviation in grains.
2) Range is the difference in weight between the heaviest and lightest cases in the test.
3) Case range weight divided by the average weight.

.243 WinchesterWhat the Numbers Mean
… And Some Speculations

Andy observes: “It certainly seems there is a huge difference in case weight between Winchester lot A and any other brand of 243 tested. What is also surprising is that there was less than one (1) grain capacity difference between all the cases, even with a 14.7 grain difference in case weight!

Should one be wary of trying the same loads that were initially tested in the light weight Winchester brass even though the capacity difference is small? I have had some interesting results with one brand brass that I cannot pass on yet, except to say I sent that company a sample of the lot I have been using. The Remington brass weight range was very low. These were taken from a box of once-fired factory ammo. I will have to acquire some more and measure it.”

Results of Larger Lapua Sample
In a previous session Andy weighed all 100 Lapua cases he had on hand. His measurements showed a total variation of 2.1 grains, with the weight range being 172.5 to 174.6 grains. That is a 1.2 percent spread. The most that came in at the same weight were 11 cases at 173.5 grains.

Permalink Bullets, Brass, Ammo, Reloading No Comments »
September 25th, 2008

Phoenix Hosts CMP Games and Creedmoor Cup in October

The 2008 Western CMP Games will take place at the Ben Avery Shooting Center north of Phoenix, Arizona on 11-19 October. The Western CMP Games Matches will take place on 11-14 October. The Creedmoor Cup Matches take place on 15-19 October. Together, these back-to-back competitions comprise one of the major West Coast events of the year for Highpower and position shooters, and there’s still time to REGISTER.


These combined matches offer activities for virtually every highpower rifle shooter–from clinics for beginning shooters to less formal Garand, Springfield and Military Rifle Matches to CMP Excellence-in-Competition Matches to NRA Registered Service and Match Rifle Highpower events. The official program is posted at You can sign-up on-line for any of the Western CMP Games or Creedmoor Cup matches at this REGISTRATION PAGE. Just fill in your contact info and select the matches you want to shoot. All data is sent via the web so you don’t even need a postage stamp.

Western Creedmoor Cup

Permalink Competition, News No Comments »