powder reduction when changing brass?

I have got a bunch of PPU brass that I want to run through my 7mm Rem Mag (looks to be good quality) However it is significantly heavier than my old Hornady brass. If I dump my standard Hornady case load in one it is definitely higher up the neck so obviously has less capacity.

How much should I reduce my load by with this thicker brass? Current Hornady brass load is 72.6gr of AR2225 with a 162gr ELD-X with no signs of pressure (below book max).

Pretty new to this reloading game so any advice gratefully accepted, cheers!

I would go back to the book starting load.
Otherwise, I think the usual recommendation is to start 10% below your current load (I.e about 65 or 66 grains in your case (excuse the pun)).

Cheers, I had heard of the 10% reduction, book min is 69gr however.

The load data on the ADI website is weird! The max loads for 2225 don't make much sense as they seem to chop and change with projectile weight, not quite the linear reduction in charge to increase in bullet weight as you'd normally expect... (max with 162gr is 73.5gr yet max with 170gr is 75gr! and 150gr is max at 72.5gr)

The word is (guide) they generally give you a starting point. Use the hodgden data as well as long as the powders are interchangeable! I try and average the data out as a starting point.
Just remember it is your face if it goes wrong!

Happen with me… Loaded couple batches of 7mm rem mag for a client and the "new" brass he supplied was a "bit" heavier and it went "wrong" up to a point… I stop and went 3gr lower to start again…
Be safe and shoot more… use a bit more common sense and save in the "long run"…

Mac

I would go 69.5 upwards…

Another trick is fill both types of cases with water to the top then weigh the water, reduce your load the percentage of weight difference and it will be pretty close to = velocity/pressure.

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Originally Posted by Walker

Another trick is fill both types of cases with water to the top then weigh the water, reduce your load the percentage of weight difference and it will be pretty close to = velocity/pressure.

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Yep I've had pretty good success with this trick as well, will get you in the ballpark.

Cheer guys!

Interesting the ppu brass is a lot more consistent in weight than my old hornady brass! PPU +/- 0.3gr, hornady +/-1.8gr. Only weighed 20 of each so small sample size.

Did the water volume technique mentioned above the PPU brass has on average 4.5% less capacity than the hornady. This seems a lot? Is this normal?

Yup ....thats why its important to reduce the load when you change any components

Would you usually reduce the load even when changing lots? Such as powder, primers or projectiles?

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Originally Posted by Oli1102

Would you usually reduce the load even when changing lots? Such as powder, primers or projectiles?

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Attention. To the not!!! “I” wouldn’t to any componente other than brass after the capacity test. If you change projectiles weigth than yes agai

Personally with a lot to lot change of same components, I would not change any thing but definitely observe closely the first loadings / firings.But a component change / substitution I would drop down a bit on loads and actually redevelop the load again.
IE: if I started using another brand or even changed up from standard to magnum primers for example I would redevelop the load.

And obviously for a change in projectile weight or style ( a 140 Grain Siera is going to create a different pressure than a 140 grain Hornady ELDM )

For Brass I would weigh to see a difference in lot to lot of same brand, initially. If its a different manufacturer work up again, ( redevelop load )