Total bullet length???

[Willem .243 musgrave]

Hey guys

So, I'm shooting a 243 with 87gr V-Max bullets @ 3200ft/s.

How regularly do I have to re-measure my total length, how fast does the lands erode? About how much loads?

It is a normal hunting rifle with a 24" barrel with a suppressor on, no bull barrel.

What I do to measure the total length is to take a fired case, put it through a neck size die slightly only so that the case neck firmly grips a bullet where you can still force it inwards with your finger. Place a bullet in the case at a very long length so that when I close my rifle bolt the lands will push the bullet deeper into the case, then i just seat my bullets about 2 thousands deeper than the measurement I get from the described procedure. This means I seat the bullets at about 2 thousands off the lands

Recently just for curiosity I applied the above method again and found that after about 600 rounds the total length has grown with about a full millimeter.

Can this be?

 

[Drop Port]

Did you save the original bullet and do the measurement with it?

 

[Raythemanroe]

I really don't understand how you could be measuring anything with the stated method. It's best to have a couple tools laying around and some paper to keep track! Like the earlier person mentioned that bullets can very a couple thousandths easy so unless you was measuring with the same bullets you have that tolerance to deal with. That being said you could be jumping .001 to .002 with one bullet and bumping with the other.. You may want to be more conservative with your seating until you accumulate the right tools to get honest measurements.

 

[Willem .243 musgrave]

I do not have one of the original bullets left, but the factories tolerances could not vary with 0.04" (1 millimeter)?

I'm still a student, do not have money for precision tools but with my method of measurement I consistantly shoot half MOA groups @ 100m (109.9 yards) and I get consistent readings when I measure how I do, I repeat the process about 7 times than take the average measurement, but the variance is vary small from the longest to shortest reading I get.

But nether the less my measuring technique, is there an answer on how many round does it take to adjust your total length on this sort of rifle?

 

[Raythemanroe]

Running roughly a 90g bullet 3200 fps I'm guessing 1500 to 2000 rnds barrel life and would guess with your method every 250 rnds I would recalibrate.