lionhunter Report post Posted August 17, 2013 I just typed up an entire page on this topic and my new computer flashed, and it all went away.. sooooo, I am going to make this short I worked up a load for my buddy's 300 wsm using win brass. we were getting average fps of 3300 ish and 1/4 in groups at 200 with more than one load. we were please.... He could not find any win brass so against my advice he bought fed brass. He said " how much difference could the brass make" well, we shot the same reload recipe using the fed brass and were getting 3500 fps and major pressure issues (flat primers, sticky bolt, etc) still getting good groups, but way too fast. we reverse engineered the cartriges when we got home thinking we had used too much powder.. nope same amount of powder. what we did learn was the fed brass weighed 7 gr more than the win brass. Have any of you experienced such a difference in speed when the only difference was the brass? Please feel free to chime in.. I have always found a good load and stuck with the exact same components, so I have not dealt with this before.... Thanks, Whitey Share this post Link to post Share on other sites
justanotherpunk Report post Posted August 17, 2013 Based on the difference in weight I would suspect it was a decrease in overall case volume. Of course this assumes the only change was the brass and you are using the same lot of primers, powder and projectiles. Pat 1 Share this post Link to post Share on other sites
Benbrown Report post Posted August 18, 2013 Well, now he knows how much difference the brass can make. Anytime you change ANY component, you should back down a bit and work your way back up--even with different lots of the same powder. Share this post Link to post Share on other sites
roninflag Report post Posted August 18, 2013 the heavier brass could , and probably does mean less case capacity. Share this post Link to post Share on other sites
pwrguy Report post Posted August 18, 2013 Well, now he knows how much difference the brass can make. Anytime you change ANY component, you should back down a bit and work your way back up--even with different lots of the same powder. Yep, specially if you are shooting loads at the top end of the powder charge. Be carefull. I wouldn't have expected that huge of a velocity change though. 1 Share this post Link to post Share on other sites
id_danman Report post Posted September 20, 2013 Seems like this a common problem with this particular round. I have seen people with similar experiences post on other forums. Any time you change brass, reduce the load and work up again. Share this post Link to post Share on other sites
firstcoueswas80 Report post Posted September 20, 2013 The Federal brass in 300 wsm is thicker then the Winchester brass, almost always causing higher pressures and speeds... I have had to go through my brass and seperate head stamps after experiening this for myself in my Kimber WSM. Share this post Link to post Share on other sites
