Bullet Comparator , seating depth and new lot of partitions

[phutch30]

This question is going to sound pretty dumb, but bear with me.I want to be sure. My original setup was done with the crimped case and the magic markered bullet. Also when I first decided on my current 7mm load I bought 2 cases? (20 boxes), of the same lot # of 160 gr partitions. Well I am rapidily using these up. I only have 1 box left. I have just started using an Bullet Comparator
.

My question is this. Due to the slight variation in ojive postion on different lot # of bullets. If the Bullet Comparator reads a different length on a shell loaded with the new lot #, say 3.380 vs the current 3.365 that I get with the old lot of partions. Should I adjust my seating depth to my old oal (made with a bullet comparator) of 3.365 to maintain the optimum distance from the lands?

 

[tjen]

Just to be sure your gage reads from the base of the Ogive not the tip of the bullet? If so that is how you determ the actual distance to the lands to be precise and consistant. However the difference in bullet lots as discribed is suspect but I mite not fully understand your discription.

 

[steve4102]

My question is this. Due to the slight variation in ojive postion on different lot # of bullets. If the oal gauge reads a different length on a shell loaded with the new lot #, say 3.380 vs the current 3.365. Should I adjust my seating depth to my old oal of 3.365 to maintain the optimum distance from the lands?

The ogive position may still be in the exact same position. What may be different is where the seating stem of your die comes in contact with the bullet. The seating stem rarely if ever contacts the bullet at the ogive.
I would adjust the die to the old OAL first.

 

[phutch30]

Ok, My bad my question was directed at the use of a Bullet Comparator that fits on the caliper. Sorry about that.
So what I am asking is this: if my old lot of 160 gr partions all load at 3.365" accourding to the Bullet Comparator and a new batch of 160gr partitions load up and measures 3.380" with the seating die adjusted for the older partions, I should adjust my seating die to seat the new bullets a little deeper, down to 3.365.
Correct?

 

[Guest]

Yep. Adjust the seating stem (or the whole die if you're seating and crimping in one step, which I advise against). If you leave it alone, you'll have a different COL, and the loads might not shoot the same.

 

[phutch30]

thought so thanks

 

[rick smith]

I would use one of the old bullets to reestablish the seating depth so you know how far off the lands it is. Then use a new bullet to find the lands and seat it the same distance off the lands. If the seater is not putting them to the same place, I wouldn't assume that using the old measurement would be right for the new lot of bullets.Rick.

 

[kraky]

In general if you had good luck at a certain seating depth you would want to go back there again. On the other hand why not try the new seat depth and see how it shoots....maybe leave 5 at the longer length. My guess is you won't see a difference at all with just .015".....then again you might get an improvement. Don't know until you try cause reloading gremlins seem to be everywhere.

 

[phutch30]

.015 puts my bullet touching the lands. So I backed off the new patitions to the old length and shot a 5 shot 5/8" group so I think its good.

Thanks everyone

 

[Guest]

Good sounds like an understatement. You'd better write down those measurements for posterity (and to be sure you correctly duplicate them again next time!).

 

[phutch30]

written down as well as a dummy round made.

 

[JD338]

written down as well as a dummy round made.

phutch30,

Perfect! You are a quick learner. Nice shooting.
You may also want to consider buying some factory seconds from Shooters Pro Shop. You will cut your bullet cost almost in half. Nothing wrong with these bullets, I use them for load development, target shooting and hunting.

JD338

 

[phutch30]

JD338-what makes them "seconds"?

 

[TScottW99]

JD338-what makes them "seconds"?

Cosmetic blemishes. They shoot just as good though. With seconds brass and bullets I have shot .25 groups in .308win and .60 in a .280Rem. Can't argue with that for 1/2 price :lol:

 

[phutch30]

can you get them online? I seem to remember buying some right from the factory when I lived in OR.

 

[TScottW99]

Here you go...

http://www.shootersproshop.com/