Reduce loads when changing Cases or primers?

[leo158]

Right now I worked up to 36.5 gr of varget shooting the 1365 sierra sbt. Groups are getting better and no signs of high pressure. If I decided to try different primers or cases.( remington cases and cci primers right now I use) Should I lower my charges? And since I am at 36.5 of varget, should I continue to increase by .5 gr till I get pressure signs or until accuracy falls off? This is still for my 22-250.Thanks all for the help. Dan

[davemuzz]

Tell me the gr. wt. of the Sierra 1365 please.

[JASmith]

General rule of thumb: "Begin with the published starting load and work up until you find your accuracy node."

This works extremely well and should be applied any time you change your components.

Also, the differences in trajectory and wind drift one sees going from the starting load to the maximum load are rarely enough to make a difference until one gets into very serious long range shooting.

Besides, working a ladder test or other load work-up routine means more trigger and bench time -- always fun and one learns a lot!

[earl39]

Tell me the gr. wt. of the Sierra 1365 please.
Dave it is a 55gr bullet.

[Shooter2112]

Leo,

The only documented load reduction recommendation I know of is CCI's recommendation to reduce loads by 1/2 grain if switching from a standard large/small rifle primer (200/400) to CCI military large/small (34/41) primers (typical magnum strength primer powder charge reduction advice). Reason given was that CCI considers their 34/41 primers to be of magnum primer strength. My Lee manual says the same thing. Below are a few links I had in my bookmarks that may or may not answer your question. What I can say is that I definitely get lower velocities using Remington primers vs. CCI or federal <and> I get higher velocities (100-200fps) grain/grain using a CCI#41 primer vs. CCI400's in my 20" AR (55gr FMJBT LC)
Cheers,
S

http://www.cci-ammunition.com/products/primers/primers.aspx?id=30
http://bulletin.accurateshooter.com/2012/03/primers-and-pressure-analysis-by-james-calhoon/
http://www.reloadingroom.com/index_files/Burn%20Rates.htm
http://www.shootersforum.com/handloading-equipment/46029-burn-rate-strengh-chart-large-small-pistol-primers.html

[leo158]

Sorry,been away for awhile. Yes its a 55 BT. I picked up some new brass also. Would I load them with the same charge as I am shooting now or should I lower the charge to fire form them? Thanks all and sorry again about slow reply back. Dan