Measuring Lands & OAL

ah141nj · January 1, 2010, 10:02 PM

Hi Guys & Happy New Year to all.

Just bought a Hornady OAL guage & comparator.
Used it in my Colt Match HBAR II.
Lands/OAL measurement was 2.010 while using the comparator.
That gives me a conventional OAL (w/o comparator) of 2.39.
Do these measurements seem accurate?
How much of bullet jump to start out with?
Should I just seat to published OAL & not use these tools?

The bullet is a Hornandy 50 gr V max. Its length is 0.768 if that helps.

champ198 · January 2, 2010, 12:35 AM

you need to go by the comparator measurement...it measures the bullets Ogive which is the first part of the bullet that touches the lands the comparator should have came with a small set screw that will go in the red part of the comparator....this is to mount it to your caliper to use to measure rounds without havin to mess with it commin off...what i do with mine is mount it on the caliper...zero the caliper...all of my measurements are taken that way....say my bullet to lands is 2.15 with comparator and insert...i start mine off at .15 off the lands...so my measure ment on a compleated round with the comparator is going to be 2.00 using the comparator...its a little funky to understand but hope this gives you the idea

Shoney · January 2, 2010, 01:52 AM

ah141nj

What is the twist of your barrel????

ah141nj · January 2, 2010, 11:39 AM

Quote:

What is the twist of your barrel????

It is 1/9.
I know the 50's may be a little light for my twist, but out of the bullets I have and tried...I got the best results with them.
Besides, I have about 1000 of them.

Bullet94 · January 3, 2010, 04:50 AM

With a 1/9 twist Colt Match HBAR II - I would recommend loading to the OAL in your manual for the bullet weight you’re shooting.
Save the OAL gauge & comparator for a bolt action rifle.

You might check out this link too -

http://www.6mmbr.com/223Rem.html

Sport45 · January 3, 2010, 05:54 AM

Can you reach anywhere near the lands with a 50 grain bullet and still have enough in the case to hold it in place? I wouldn't try to load them longer than mag length which I believe is 2.260"

January 1, 2010, 10:02 PM	#1
ah141nj Member Join Date: November 6, 2008 Location: NJ Posts: 76	Measuring Lands & OAL Hi Guys & Happy New Year to all. Just bought a Hornady OAL guage & comparator. Used it in my Colt Match HBAR II. Lands/OAL measurement was 2.010 while using the comparator. That gives me a conventional OAL (w/o comparator) of 2.39. Do these measurements seem accurate? How much of bullet jump to start out with? Should I just seat to published OAL & not use these tools? The bullet is a Hornandy 50 gr V max. Its length is 0.768 if that helps. __________________ There's no such thing as a good gun. There's no such thing as a bad gun. A gun in the hands of a bad man is a very dangerous thing. A gun in the hands of a good person is no danger to anyone except the bad guys." -- Charlton Heston, 15 Sep 1997

January 2, 2010, 01:52 AM	#3
Shoney Senior Member Join Date: February 21, 2002 Location: Transplanted from Montana Posts: 2,311	ah141nj What is the twist of your barrel???? __________________ I pledge allegiance to the Flag - - -, and to the Republic for which it stands….Our Forefathers were brilliant for giving us a Republic, not a democracy! Do you know the difference??? and WHY?http://www.wallbuilders.com/LIBissue...les.asp?id=111

January 3, 2010, 04:50 AM	#5
Bullet94 Senior Member Join Date: September 8, 2004 Location: Kansas Posts: 723	With a 1/9 twist Colt Match HBAR II - I would recommend loading to the OAL in your manual for the bullet weight you’re shooting. Save the OAL gauge & comparator for a bolt action rifle. You might check out this link too - http://www.6mmbr.com/223Rem.html __________________ PRO-SECOND AMENDMENT - Live Free or Die

January 3, 2010, 05:54 AM	#6
Sport45 Senior Member Join Date: May 25, 1999 Location: Too close to Houston Posts: 4,196	Can you reach anywhere near the lands with a 50 grain bullet and still have enough in the case to hold it in place? I wouldn't try to load them longer than mag length which I believe is 2.260" __________________ Proud member of the NRA and Texas State Rifle Association. Registered and active voter.

January 2, 2010, 12:35 AM	#2
champ198 Senior Member Join Date: June 30, 2008 Posts: 217	you need to go by the comparator measurement...it measures the bullets Ogive which is the first part of the bullet that touches the lands the comparator should have came with a small set screw that will go in the red part of the comparator....this is to mount it to your caliper to use to measure rounds without havin to mess with it commin off...what i do with mine is mount it on the caliper...zero the caliper...all of my measurements are taken that way....say my bullet to lands is 2.15 with comparator and insert...i start mine off at .15 off the lands...so my measure ment on a compleated round with the comparator is going to be 2.00 using the comparator...its a little funky to understand but hope this gives you the idea