Bullet seating depth?

[karlrudin]

From what I have been reading, cast bullets tend to like to be seated at least touching the lands of the barrel so as to get lined up correctly and start off straight versus jumping like "J" bullets. Well I set my die so as my bullet would be slightly engraved on the bullet then backed off to where it left no mark on the bullet. Then I took the overall measurement. I started loading up a box of 20 and constantly had to work with the seating die to keep the over all length the same as the first cartridge. Well I shot that box after running a couple of fouling shots. The bullets would group, then a flyer. Do it again, group well, then a flyer. No specific amount of bullets before or after the flyer. Along with that, the bolt on closing sometimes was stiff, sometimes not. I made sure to keep the over all bullet length the same within .001" So my thought and question is this, should I not worry about the over all length being consistent and concentrate more on where the bullet ogive touches the lands. This concept seems more correct to me. Remarks encouraged [smilie=b:

[Love Life]

Get a comparator and sort your bullets with that.

[largom]

Your mistake was going by the overall length to the boolits tip/nose. You need to measure to the boolits ogive. Boolit noses can easily be changed by several thousands especially if your seating die pushes on the nose or does not fit the profile of your boolit.

Larry

[Yodogsandman]

You might be bumping up the boolit diameter when sizing. I recently found myself bumping up the noses with the NOE 269-145 boolits. I sized them just an hour after heat treating. These are long thin boolits and easily bent too. The gas checks went on tight and I was giving a little extra push at the end of the stroke to be sure the GC's seated square. I found that being .006" over jacketed diameter they didn't fit in the seating die right, either. I got a die set one caliber size up and used it to seat the boolits with that seater die. I used a 270 Win seater die instead of the 6.5x55. My land diameter is just shy of .266" and the boolits drop from the mold at .266".

[35 shooter]

Agree with using a comparator, though at this time i'm not, i think it's always a good idea.
Wrong lube for the job can cause flyers. Usually there will be a pattern as to about how many shots before it happens, but i found out it can actually be kind of random also.
Don't know how fast or what your load is, but speed or pressure versus twist can cause it if you get on the ragged edge.
I seat to touch the lands when possible, but have one boolit i found didn't like that because the nose band was touching pretty hard in the throat. Backed off till there was just bare contact in that area and found a good place to be with that one.
Could be any one of several things...guess that's lots of help huh?

[Love Life]

Sorting your boolits with a comparator ensures a consistent base to ogive batch. When seating, measure the OAL of the loaded rd from the base of the case to the ogive. This gives you a consistent jump or jam. Measuring from the base of the case to the bullet tip will not give you a consistent jump which means your "consistent" seating depth...isn't.

[karlrudin]

Well after I got out the bullet comparator, I started all over with the over all length. I put a bullet in a fired case, seated long, then put it in the chamber, closed then open the bolt and took the measurement of the cartridge. While checking the bullet with the comparator, I found that the nose and shank of the bullet up to the ridge on the bullet were .277, and that the bullet nose and shank would go in the bore with a little resistance. From what I've read, isn't the nose suppose to be .001-.002 larger than the lands of the bore. The ridges are at .285. So my comparator stopped just short of the first ridge. And this is where I took my measurement and loaded up ten to see what they are going to do. I will be trying some time this week and give y'all an up date.

[karlrudin]

Well an update on using the comparator, didn't make any difference. Groups were still inconsistent. My decision, I'm going to go with a heavier bullet and start from scratch for 100 yards. I know I shouldn't be complaining about 1.5 to 2.0 inch groups, but I am :) A nice man on this forum gave me some sample bullets to try earlier this year and I"m going to get to them now. They are 160 Lyman. Maybe these will work out a little better at range. Will try to keep everyone up to date as things progress. I did find out one thing from all of this though. I have tried 4 different powders so far, and they all liked IMR 4064 as a powder vs the faster burning ones. According to what I have read everywhere EXCEPT from NRA Cast Bullets, fast burning powders are what are suppose to work. After reading through the NRA manual and using their suggestion on the slower burning powder, my groups did tend to be more consistent although it was only a little smaller. I can definitely live with more consistent.

[kungfustyle]

What gas checks are you using? They might be throwing off. Me I'dd be doing back hand springs w/ a 1.5" group. If you are capable of better then, weight the boolits and keep them in lots of .5grns or less. Try Hornady gas checks or super glue them on. Try to seat the gas check using your press, then sizing the boolits. Trim the cases. But with 1.5" groups sounds like you do mostly right, right now. Faster burning powder w/ Dacron may help.

[leftiye]

Your mistake was going by the overall length to the boolits tip/nose. You need to measure to the boolits ogive. Boolit noses can easily be changed by several thousands especially if your seating die pushes on the nose or does not fit the profile of your boolit. Larry

What he said. Your overall length variations were being caused by the seating die contacting the ogive (not the tip) of the boolit. In other words, the boolits would have probly contacted the rifling correctly as seated if you had left the die alone. Your fliers may have been caused by another issue altogether though.

[karlrudin]

Well an update using the Lyman 160's silhouette bullet. Like I said they were given to me by a very nice man here and the specs he gave me on the bullet were 165 grain coww water dropped, sized .285 and lubed with carnuba. My overall cartridge had the bullet ogive of .285 just touching the lands. I found the tightest group at 36.5 grains of IMR 4064, no crimp, no poly fill. Overall group was .784". Now I have recently received for Father's Day, my very own Lyman mold. Load tweeking will commence. Thanks yall for all of your replies. I try to keep yall updated to show that your comments are being put to good use. :)