I may have gotten a bit anal on this subject, but I dove into the subject of inconsistent Cartridge C.O.L. over the past several weeks, some of this information I obtained directly from RCBS and LEE. Keep in mind that I'm parroting some of the information I obtained from RCBS LEE, and Holland. I wanted to share some of my 60 years of experience on this subject with re-loaders should they experience inconsistency with cartridge overall length (C.O.L.) when seating bullets.

First the C.O.L. is obviously based on the cartridge base to a point on the bullet ogive, as its done when using and setting up bullet seating dies.

In addressing variations in bullet ogive I first seated a test sample of Berry’s bullets to a cartridge C.O.L. of 2.250 +- .002 using a caliper to insure a relative consistent C.O.L. of 2.250, again according to caliper measurement. I then used an RCBS micrometer that measures from the cartridge base to the ogive. Measuring from the base to the ogive I found that many bullet’s ogive profile was inconsistent and caused the C.O.L. to vary as much as .015, this is not good. So in many cases the bullets, when they’re struck, are not consistent and you could experience C.O.L variations of as much as .015 or more. Keeping in mind again that your seating die/seating plug is measuring from the cartridge base to the ogive when setting up for a specific C.O.L.. Much of it depends on the quality of the bullet.

The C.O.L. problem lends itself to several issues.

1. First your seating die/seating plug is measuring from the cartridge base to a point on the ogive.

2. During the bullet manufacturing process, when bulk bullets are struck, if the equipment setup isn’t in near perfect condition (tolerance precise), the bullet ogive profile can vary regardless of the seating dies/plugs being used.

3. The machining of the seating plug is critical in terms of the seating plug profile (angle) and depth. If the seating plug machining is not precise, or if the tooling is worn, an inaccurate profile and depth will result affecting the C.O.L.. I learned that Redding seating plugs are actually precision ground and lapped. I can’t speak for LEE dies, but in my discussions with RCBS they indicated that RCBS seating plugs were not precision ground and lapped.

4. There’s another problem with bullet seating plugs, in general seating plugs are not necessarily individually dimensionally precise for the a specific bullet/caliber. For example, Hornady seating plugs for .22 Cal are machined to accommodate a range of grain weights and specific bullet styles, therefore the seating plug profile will not be specific but accommodate a range of various grain weights which can affect the bullet profile dimensionally. All of this can affect how the seating plug contacts the bullet profile and eventual C.O.L.. In reality you would need a specific seating plug machined and ground for the specific bullet you’re using. Note: The Holland's Bullet Comparator mentioned in this documentions is used exclusively by Sierra Bullets on their production line to accommodate this issue.

5. In order to deal with this problem you need a "bullet comparator" which is a precision measuring tool used to examine the bullet profile, not a caliper style bullet comparator, you’ll need a bullet comparator like the Holland Bullet Comparator which is the absolute best available to the reloader, it’s stated as the gold standard, this device is a precision bullet measuring tool that measures only the bullet, bullet base to ogive, within +/- 0.0003 (not cartridge base to ogive), it also uses bullet guides when measuring. It’s not cheap, approximately $225.00 + S&H, but when you’re looking for C.O.L. precision or bullet seating repeatability for a rifle bullet this is the tool I recommend to insure C.O.L. consistency.

It can be very aggravating when one encounters a C.O.L. that varies all over the place when seating bullets and having to constantly adjust the seating die. Personally I use a Holland Bullet Comparator, a bullet micrometer, and a precision micrometer adjusting screw that screws into the seating die. They make these accessories for both pistol and rifle dies. Using these reloading accessories insures that you will always be able to maintain a C.O.L. during the bullet seating operation.

6. The quality of the bullet also becomes critical, in general cheaper bulk bullets can result in wider bullet profile tolerances and affect the C.O.L.. The only way to improve the C.O.L. is to possibly use match grade bullets or sort bullets to maintain a closer C.O.L., this is where the Holland Bullet Comparator comes in. Be careful from whom you purchase reloading bullets.

There will always be some tolerance variation in bullets and so is the case with seating plugs, it just depends on the quality of the bullets and seating dies/plugs being used and the precision you're trying to achieve.

As far as flight of the bullet is concerned, it’s extremely important that the bullet be as perfect as possible in terms of being concentric, if not, this may well be why we often experience occasional fliers, or problems with inconsistent repeatability of the point of impact.

So if one is looking for precision, I would sugest that the reloader would have to start with choosing quality grade bullets, bulk plinking bullets are OK, but if one is looking for precision better quality bullets will be necessary, perhaps something like Hornady, or Nosler bullets and a Holland Bullet Comparator.

That's what I’ve learned over the years from addressing this subject with RCBS, LEE, and Holland. By the way, RCBS is always very cooperative in discussing any reloading issues over the phone, LEE is much more difficult to contact to discuss any reloading issues. Also, there’s no question that many bulk rifle bullets vary in the bullet ogive profile dimensionally, which is problematic when seating bullets to a specific C.O.L.. Remember that a bullet micrometer typically checks a loaded cartridge from the base to ogive, the only way to insure bullet quality and consistency is to use a Holland Bullet Comparator that checks the bullet itself individually.

Here's the link to the Holland Bullet Comparator and a video of how it works:

"https://www.hollandguns.com/32m7/parts-accessories/reloading-accessories.html" \t "_blank"　

Video:

https://www.youtube.com/watch?v=fe4AUwl-Ho0

Bob’s Bullets are taughted as being truly match grade. They state that Bobs’ Bullets produces only the finest quality match-grade bulk .223 bullets for demanding target shooters and competitive marksmen. You will not find a more superior bulk reloading bullet at this price anywhere.　

Their bullets may be truly match grade, however, the only way to validate this claim requires that a sufficient sample be verified with an instrument like the Holland Bullet Comparator to insure the relationship of the bullet profile/ogive, basically it’s a method of sorting bullets into groups so they have the same dimensionally characteristics.

In order to validate bullet quality claims requires the necessary measuring instruments on the production line, Sierra Bullets actually utilizes a Holland Bullet Comparator when manufacturing bullets.

So be careful of what someone claims, ask them if they can produce evidence that their manufacturing facility owns and uses precision measuring instruments when manufacturing bullets.

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4. Are LEE Reloading Dies Any Good