[Full MeTal Jack]

I dont have a chronograph, but when someone at range has one I ask if they'll fire a couple of my hand loads.
Thought I did a maticuless job of weighing powder.
Bushmaster AR CMP Competition :assult:
77 grain Serrias, 23 grains IMR 4895
3 shots:
1. 2565
2. 2540
3. 2573 fps

8 and 15 fps is very resonable.
But 33 fps difference, is this normal?
All new Winchester cases. As of writting this thread I recall I did not resize new cases. ( will that make a difference?) Have seen that disclaimer before for new brass. Hmmmm?
Also reamed the flash hole.

2570 fps, that can be pushed beyond 2700fps? Not much loading data for heavier bullets. 62 grain all kinds of recipes.

Any and all thoughts?

[Mooseman684]

I don't have any data in my books for that heavy bullet in .223 , but Shaun may have some since he is in the business. As far as velocity differences, I can only think it may be due to temperature changes, Barrel warming, but even Match ammo can vary 50 fps due to these factors.

[Joey l mur]

If you are not precision loading that is not bad. When I say precision loading I mean alot.
When I precision load I Full body size my casings trim and mesure all the exterier dimentions including the flash holes.
Itry to keep to a tolerance of +.0005 or -.0005 inch of each mesure. That is a .001 inch tolerance I have mikes that mesure 1/10 of 1/1000 of 1 inch.
Then I sort them by maker, each maker uses a slitly difrent alloy with a slitly difrent densety.
After sorting by maker I weigh each case and sort by weight. With the outsides the same dimentions, the alloy the same and the weight the same the volume should be the same.
Then I weigh the bullets and sort them by weight. I got some match graid sierra bullets that varied as much as 10 gr.
After I load the primers I weigh each load of powder as tight to the exact same weight as posible.
Then I seat the bullets of the same weight in the cases of the same volume with powder of the same weight with the same seating.
Digital scales are a god send in this type of loading. However you can see what I mean by precision loading. In theory you should be able to place a bullet in the same hole as the one befor it.
Match grade Rounds are not as precision assembled as this as they vary as much as 5%. :cheer:

[Full MeTal Jack]

Have'nt weighed cases. Will check and see. Volumetric differences is various manufactures cases is understood.
I weighed match 30 cal bullets before and pulled some to the side to load seperately. Next batch I'll weigh bullets even though I checked several bullets at random.
Useing balance type scale seems weighs vary due to weight distribution of powder. Hmmm?
Yes, this frugal reloading is sooooo time consuming!
Thanks

[Joey l mur]

Digital scales save you a lot of time in precision loading also balince scales will be thrown out if the case is not on just right.:guitar: