bullet drop at 1000 yards, new v fired cases

[Topshot]

I have been shooting a load of 93 grains of H1000 behind a 300 grain SMK out of my .338 Edge. Primer is CCI 250 magnum.

I have noticed that loads using "new" Remington brass shoot on average just over 1 MOA lower at 1000 yards than the same load using once fired brass.

Can anyone come up with an explanation for this?

[Michael Eichele]

Originally Posted by Topshot

I have been shooting a load of 93 grains of H1000 behind a 300 grain SMK out of my .338 Edge. Primer is CCI 250 magnum.

I have noticed that loads using "new" Remington brass shoot on average just over 1 MOA lower at 1000 yards than the same load using once fired brass.

Can anyone come up with an explanation for this?

I dont know your reloading process such as if you neck size only etc.....But something I have found in the past (at least with chambers that are not tight) is that firing new brass or full length size brass versus neck sized only brass shows a velocity difference.

Check your loads side by side over a chrony. You may be suprised what you find.

[Topshot]

Mike,
I us a set of D.E. .338 Edge dies.

The new brass is run through the FLS die to straighten out the necks and then loaded.

The once fired and now fireformed brass is sized with the FLS die backed off 3/4 turn prior to loading.

[Bravo 4]

I would say that if everything is the same-powder/ primer/bullet lots and same environmental conditions...compair the weight of the new versus the older brass.

[davewilson]

can i ask what difference in brass weight would have to do with anything?

[Bravo 4]

I have noticed some inconsistency with my Remington Ultra Mag brass. I have weighed some from a new lot and compaired it to the older brass it was replacing and there was enough difference that I would say the newer brass' case walls were thinner. An average of a few grains of water difference confirmed this. This could cause a change in the pressure in the same load, which can change velocity. All is needed for my .338 EDGE to have a different POI of 1moa @ 1000yards is about 40fps. If he were to chrono them and confirm a velocity difference between the two loads...then all I'm saying is the brass could be the culprit.

[Michael Eichele]

Originally Posted by davewilson

can i ask what difference in brass weight would have to do with anything?

Typically heavier brass is thicker. Thicker brass meens less volume. Less volume equals higher pressure. Higher pressure in this context will equal higher velocities. The opposite will happen with lighter brass.