What is this telling me?

[randyman]

Sometimes my brain locks up and even the simple things can be confusing so please humor me with what may seem like a simple question.
In a different post, I submitted a photo of some .32 gr. lead-free bullets that I weighed on my Chargemaster Lite scale that showed a wide range of weights. After sorting them into individual bags so I can load groups of similar weights I then measured them from base to ogive as seen in the photo.
I fully understand how bullets of different weights can affect my shot groups but what/how does the length of the bullet affect? As the bullet is going into the seater die what portion of the bullet is contacting the die to establish seating depth? I have both the RCBS competition seating die and a Redding type S match die set with bushings. I use the RCBS dies for the .204 and the Redding dies for the .20VT.
This whole exercise is strictly for bench shooting as I work up different loads to find what shoots best in my rifles. I won't be so OCD when it comes time to load for shooting rats in the sage but I want to find what shoots best off the bench. Any help/advice is appreciated. Thanks, Randy.

.32 gr. lead free measured.jpg

[randyman]

.32 gr. lead free measured.jpg (78.92 KiB) Viewed 3324 times

I see the photo didn't attach as planned-trying again

[Bill K]

Just another example of if you want the best reloads, match everything as best you can.. but for everyday average critter shooting, you really don't have spend all that amount of time, unless you just want to do something on cold and wet days inside the loading room. Bill K

[skipper]

Let's start by saying that bullets can and do vary in measurement from ogive to tip. This fact can lead to bullet seating issues. The seating die should contact/push the bullet into the case from the ogive NOT from the very tip. This uniforms a loaded bullet's relationship between the ogive and chamber throat. Each bullet has the same jump to the lands. Some seating dies have been known to contact/push the bullet from the very tip. Those dies will seat bullets with different ogive to throat distances simply because of the variation in measurement of ogive to tip from bullet to bullet. A seating die that seats bullets from the ogive may appear to have varying COALs when measured from the base to tip without a comparator simply because the tip to ogive variation.

Sort your bullets by weight first. Then sort each of those lines of bullets of the same weight by bearing surface, base to ogive, secondly. That way each line is matched by weight and also in order by bearing surface.

[randyman]

Thanks Skipper. That's the way I understood it but wanted to confirm my suspicions before loading these up again. I pulled all these bullets from rounds I had loaded prior to weighing them. Again, these are not my hunting rounds and are for load development.
To continue this discussion a bit, do all these different measurements mean that I'll be seating the longer bullets deeper in the cases and thus increasing pressure? I don't want to get too anal about this but it gives me a better understanding of whats going on during the reloading process. I've got .008 difference in the lengths of these bullets and don't know if that's enough to worry about or if i should pick the average length and load to that. For load development I'll probably adjust the seater die for each weight group. For my hunting rounds I'll probably go with the average. Randy.

[skipper]

Don't adjust the seating die for each weight bullet. It's more important to have each ogive the same distance from the lands. Once you set the distance from ogive to lands stick with it. There will probably be different pressure for each round, but the spread should be minimal. if you really go anal about reloading you might end up scrutinizing the base of each bullet to be sure that they will exit the barrel crown evenly.

I would say that uniforming the COAL as measured from base of the cartridge to the ogive of the seated bullet would be worthwhile. Weight sorting bullets and also sorting by bearing length would be worthwhile. Uniforming each case as closely as possible and then weight sorting them is beneficial. Neck tension would also be something that you might want to try to uniform. I would suggest an arbor press with strain gauge for that job. You will invariably end up doing some sort of prep on the insides of your case necks AND turning the outside of each case.

Look at your rifle also. Make sure the crown is cut evenly. Some whiteout on the end of the crown may reveal the pattern of the escaping gas there. After a few rounds a star pattern should appear giving you a picture of the uniformity of the crown. Make sure that you do not have a carbon ring forming in the throat of your chamber. If the crown is uneven you can have it recrowned by a competent gunsmith. If that is the case you might even consider having your chamber recut with a custom reamer that will allow you to reach the lands and grooves. Pacific Tool and Gauge can fix you up there. Then your bullets will have a better chance of entering the lands and grooves straight versus randomly from that jump to the lands and grooves from most production chambers. If you can load your rounds so that you are jamming your bullets into the lands and grooves you will probably see an increase in accuracy. You'll just have to ask yourself how far you're willing to go to achieve O% deviation from round to round. AccurateShooter.com has a vast knowledge base to draw on from some of the top shooters in the nation. Lurk around there for more tips.