c.o.a.l. changes

[quickdeath]

good morning,,,had 5 left over of 125 grain bt's in 30 caliber and started a new box of the same,,,different lot numbers though,,,came up with a higher difference of .0016 in c.o.a.l. in the new ones,,,taken from noslers #5,,,308 cartridge,imr 4320,winchester cases,trimmed to 2.005,cci 200 lrp, and a dose of 47.5 of powder with a 125 grain bt,,,my question is seating the bullet .0016 deeper going to raise pressure and should i start all over in my ladder round,,,i am at at my last stages of perfecting this round,,,44 grains gave me a 3/4 inch group of 3,,,do i start over or continue,,,thanks :grin: :grin: :grin:

 

[Guest]

Any time I change lot numbers of bullets, primers, powder, or brass, I drop back about 5% and work back up. lt's just a precaution to ensure against any ill effects from just the kind of lot-to-lot deviations you found. Run through three rounds 5% below, three rounds 2% below, and then your loads. If you're going to have pressure issues, they should show up in that workup.

 

[bobbyrum]

Quickdeath, on advise from those who are a lot more knowledgeable than I, I always recalculate c.o.l. in my cartridges when going to a new lot of bullets. I now know my chamber lengths & I use the Stoney Point case length measuring device & comparator. I was on a moose hunt 3 years ago & using my 7mm RUM with 160 Nosler Comb. Tech. Part. Golds. When placing the cartridge into my Ruger #1's chamber & closing the action, I damn near didn't get it closed! I had used a new lot of bullets & didn't relize the c.o.l. was longer. I had been measuring to the tips instead of the ogive.
Fortunately, I had a few of the older lot with me (still didn't get a shot at a moose!

 

[rick smith]

If you really mean one thousant of an inch, should not be a measurable change in pressure. Pressure will increase quicker if you are seating into the lands. Decreasing internal volume by seating deeper will have more of an effect in pistol cases where one is using fast burning powder in a small volume case.Rick.

 

[quickdeath]

good afternoon,,,well i went to the range today shooting the old box of 125 bt's and was very pleased,,,made a mistake in a decimal point in my first thread,,,should of read .016,however all my rifles are hunting rifles,,,i go by saami's aol in the nosler book,so i will continue to work up my load,,,all bullets are seated to an aol of 2.815 so i should be fine,,,enclosed are pics of this recent shoot,,,i should stop at the 45 grainer though,,,thanks for all your help and may god bless :grin: :grin: :grin: :grin:

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