RWS vs. Lapua brass


February 23, 2010, 06:15 PM
I recently obtained 300 pieces of virgin RWS brass (at great pains to my wallet) for a new custom .300 WinMag rifle. But having no prior experience with this brand, I was shocked to discover just how incredibly heavy it is. Just to illustrate here, I took 100 pieces of this new Lapua brass I've had for years and 100 pieces of the RWS stuff (both of the .300 WinMag species, of course) and started sorting them by weight, finding that the RWS brass is by comparison to the Lapau brass FAR heavier. While the average Lapua .300 WinMag case weighs around 216 grains, the average RWS .300 WinMag case weighs around 270 grains!!!

Now just how is this going to affect the way I handload? I know, for starters, that I'd better use ALOT less powder in assembling loads with the RWS cases. But what other recommendations does anyone have?

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February 23, 2010, 07:53 PM
Try comparing the capacity of the two brands. That will have a bigger effect than case weight. The differences in weights could be due to different brass compositions.

If the volume is substantially different you will want to reduce loads more than normal during load development.

February 24, 2010, 08:25 AM
Agreed, easy way is to use water to fill the case and weigh the weight of the water. You will likely find the difference in the volume is not as substantially different as the mass of the case due to different brass compositions (as stated above). However we may be surprised by your results, RWS may have a thicker case head and therefore reduced volume.
Keep us posted, I'm interested to learn.

May 18, 2010, 05:43 PM
The Lapua cases are filled to the shoulder with 76 grains of RL22, the RWS cases with only 73 grains. Though, I haven't completed and then gone to lighting loads with either of these respective charges. I have tried up to 75 grains even in the Lapua cases using 190-gr MatchKings and was delighted at the results - no excessive pressure signs and exceptional accuracy in this particular rifle. Meanwhile, no loads have yet been tested using the RWS cases.

May 19, 2010, 04:53 AM
I personally find Lapua Brass to be more consistent than RWS. Also in the .300 WM I found RWS brass becoming more difficult to work with quicker than Lapua.

May 24, 2010, 02:43 PM
Norma's free flyer has 2 different sets of load data for 300 Win Mag. One for 215g, the other for 270g. Load data is different by about 2grains or so.

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