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Chamber measurement seems short

turbohardtop

Sergeant
Full Member
Minuteman
Mar 1, 2010
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Austin, TX
I am using the Hornady COAL measurement tool and my measurements seem a little short. With the 168gr Sierra Match King it is around 2.807" but with the 168 AMAX's it is only 1.765" Is this possible? I will try to take the measurements again to verify but does this seem accurate?
 
Re: Chamber measurement seems short

I am away from the numbers that I measured using the Hornady tool so I am going on memory.
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Your numbers appear to be a mixing and matching OGIVE and COAL, OR your measuring techniques needs some fine tuning.

Double check your technique and numbers...just measuring COAL without the Hornady tool should give you numbers closer than 0.100 to the 2.810 SAMMI value. I suspect the tool is not seating correctly on the bullet making it hang up in the throat OR not being the correct position to meaure from.

Comparing the lengths of the AMAX and SMK bullets would also shed some light on the problem and give you some confidence in your ultimate solution (they should be fairly close).

Hope this helps...
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Re: Chamber measurement seems short

I'm sure you already know this. But I'll remind you any way.

When you change from XXX bullets to ZZZ bullets there is a strong chance that the ogive numbers will change. I'm using the word ogive as a bullet maker now. One use of the word means the angle or radius from the full outside diameter to the point. As this number changes on the bullet design, the measurement will change of where the bullet will actually be the same diameter where it contacts the lands of the rifling in the barrel.

When you measure this bullet against a different make or design, you are basically comparing apples to oranges. The best way to go on these things, at least for me, is to make a chart or keep notes of measurements of Over All Length and use the same cartridge and measure the base to ogive measurement. I neormally measure 3 to 5 and make an average of those numbers.

To feed in your magazine the rifle doesn't know if you set the length from base to ogive or OAL. But in this case the OAL is what you need to remember.

Good luck in your choices.
 
Re: Chamber measurement seems short

I've found that I make a round for each different bullet type and keep that handy as a referance when I'm reloading.
These rounds have NO primer or powder in them.
Then when I reload a bullet type, I can measure that round from the ogive and set the bullet seater to the correct distance and I'm GTG.
Save time.
 
Re: Chamber measurement seems short

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rarebreed93</div><div class="ubbcode-body">I've found that I make a round for each different bullet type and keep that handy as a referance when I'm reloading.
These rounds have NO primer or powder in them.
Then when I reload a bullet type, I can measure that round from the ogive and set the bullet seater to the correct distance and I'm GTG.
Save time. </div></div>

+1... What I did before I had the correct measuring tools. That's a very good way to keep things adjusted correctly. I also use a very fine tip Sharpie marker to write the bullet name & number on the side of the case. (Most bullet makers have a model or design number located somewhere on the box.)