Bullet Lot Numbers

[Bob3700]

When ordering bullets, most request the same lot number for consistency.

Here is my question: Have you actually seen a change in zero due to different bullet lot numbers?

The answer that you give may depend on your discipline. So when/if you reply, please state the discipline that you shoot in.

As a sling shooter with either scope or irons, I can say that my zero may be a click or two off on different days even using the same load and lot of bullets. I believe that there are many other factors that affect the bullets POI other than the lot number on the box.

Am wondering if this falls under the "If you think it matters, it does" category.

Bob

 

[6Creed73]

I've shot mixed lots before where I couldn't tell the difference. The weight and BTO measurements were consistent. But I prefer the same lots because on those bullets where the BTO was the same, where the seating stem contacted bullet varied by up to 0.011. I'm very picky about my seating depths being precise.

 

[K22]

Varmint and predator hunting, recreational target shooting at the range.

No, I never could detect any differences that I could attribute to changes in bullet lot numbers, but I am only shooting the sub 1 moa world even though I strive for 1/2 moa for my varmint reload.

 

[RegionRat]

Got a surprise once in a MR match when burning up odds and ends of SMK 80 in 223.
I didn't catch that they pointed them at the factory and it made a difference.

On a different occasion, I was making up hunting loads with .30 cal SGK 165.
I was running short and was given a box from a different year and it gave seating forces that were noticeably different. They didn't shoot with the typical ones by the time you were 300 yards out, so that box became practice rounds.

 

[Straightshooter1]

When ordering bullets, most request the same lot number for consistency.

Here is my question: Have you actually seen a change in zero due to different bullet lot numbers?

The answer that you give may depend on your discipline. So when/if you reply, please state the discipline that you shoot in.

As a sling shooter with either scope or irons, I can say that my zero may be a click or two off on different days even using the same load and lot of bullets. I believe that there are many other factors that affect the bullets POI other than the lot number on the box.

Am wondering if this falls under the "If you think it matters, it does" category.

Bob

Depending on the manufacturer, there can be significant difference from lot to lot that definitely effects the POI. I target shoot off a bench and have measured different lots and tested them to see how much difference there might be. For example, back in 2018 I had two different lots of 168 SMK's that had bearing surface lengths that varied by .033" that resulted in an average velocity difference of 37 fps with a POI shift of ~1/4" at 100 yds. and the change in group size and mean radius (40 rounds fired, 20 at one end of the spectrum and 20 at the other).

Whenever I get a new lot, I'll measure them to see if there's enough of a difference to effect POI. I shoot Bergers and SMK's and seldom, if ever, find enough difference in Bergers to warrant any concern, but sometimes, not often, with SMK's there can be enough difference.

 

[Bob3700]

Depending on the manufacturer, there can be significant difference from lot to lot that definitely effects the POI. I target shoot off a bench and have measured different lots and tested them to see how much difference there might be. For example, back in 2018 I had two different lots of 168 SMK's that had bearing surface lengths that varied by .033" that resulted in an average velocity difference of 37 fps with a POI shift of ~1/4" at 100 yds. and the change in group size and mean radius (40 rounds fired, 20 at one end of the spectrum and 20 at the other).

Whenever I get a new lot, I'll measure them to see if there's enough of a difference to effect POI. I shoot Bergers and SMK's and seldom, if ever, find enough difference in Bergers to warrant any concern, but sometimes, not often, with SMK's there can be enough difference.

Depending on how u measure Berger’s, they can have similar variances to SMKs.

How often do u go to the range with the same lot of bullets and never touch the elevation knob to zero up? A change in atmospherics is sufficient to generate a 1 click difference in POI. With iron sights, what u are seeing that day affects ur zero a click or two.

Granted, pointed Vs not pointed certainly affects POI.

 

[dcali]

It depends on the specific bullets and what your standard of accuracy is. If you're aiming for F class/Benchrest levels of accuracy, mixed lots are wholly unacceptable. For just about anything else, it's fine. Of course, some bullets have better lot to lot consistency than others. Milage may vary.

When I was developing my bullets I was testing various details, and was shooting what would be considered different lots - probably a bit worse. After my session I had a few of each left over and shot them into a single group. Bullets that were shooting in the .1-.2 MOA range shot a .7" group when mixed together. That might be a bit more extreme than normal lot to lot variation (certainly, it is of mine - these were intentionally not consistent), but it's illustrative of the problem.

 

[243winxb]

1/2" to 3" @100 yards, when changing lot number. Rem 40x , varmint/woodchuck.

Every component now gets a lot number, if it doesnt have one already. Recorded in bound book with all data.