November 6, 2013, 01:49 PM | #1 |
Senior Member
Join Date: January 10, 2012
Posts: 3,881
|
OAL for an AR ?
I have two AR 15's one with a 16" 1 in 8 barrel and one with a 20" 1 in 9 barrel. I was reloading different bullets to different OAL according to the bullet manufacturers. Then I decided to load them all to 2.255 and was surprised to find they all shot better with the longer OAL.
Has anyone else found this to be the case with your OAL ? |
November 6, 2013, 02:09 PM | #2 |
Senior Member
Join Date: May 1, 2009
Location: Burnet, TX
Posts: 727
|
Not always. With blunt nosed soft points (like the 70gr Speer SP) when I started getting near 2.230" I started running into feeding issues. I have achieved excellent accuracy with all my loads (3/4 MOA) and have not needed to try to seat longer out. With 55 gr Hornady SP (w/ cannelure) I seat to 2.195" and it also starts to have feeding issues if I start seating it extra long.
__________________
Veteran OEF (2002) and OIF1 (2003) - US Army Member of the Burnet Gun Fighters, Inc. and of course the NRA Oregon State University alum -- Go Beavs! |
November 6, 2013, 02:12 PM | #3 |
Senior Member
Join Date: January 10, 2012
Posts: 3,881
|
I have not had a feeding issue with either of my AR's
|
November 6, 2013, 02:25 PM | #4 |
Senior Member
Join Date: February 15, 2009
Posts: 8,927
|
Most cartridges shoot most accurate with the longest OAL the chamber will allow. That reduced the amount of bullet tip as they enter the rifling. The further they jump to the rifling, the greater chance they'll enter a bit tipped. That slightly deforms them and too much deformation degrades accuracy.
It's easily seen if one makes ammo good enough and shoots it in rifles good enough to see the difference. Many competitors loading rounds one at a time "chase the leade" seating bullets out far enough to just touch the lands when chambered. OAL has to increase as the rifling erodes away. |
November 6, 2013, 02:28 PM | #5 |
Staff
Join Date: March 4, 2005
Location: Ohio
Posts: 21,057
|
Rebs,
You're probably not shooting a blunt bullet shape, so you can seat longer without feed problems. There are no guaranteed magic COL's. Bart's right about the trend for common tangent ogive shapes, but you just have to experiment with finding with each bullet and chamber combination to be sure. Berger's procedure for VLD shaped bullets will do OK for most bullets if you use the smaller change number per step.
__________________
Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle |
November 6, 2013, 02:30 PM | #6 |
Member
Join Date: March 4, 2013
Posts: 80
|
With the AR I load to fit the magazine. I haven't found that going any shorter helps any. Obviously I can't go any longer and still feed from a magazine.
|
November 6, 2013, 02:42 PM | #7 |
Staff
Join Date: March 4, 2005
Location: Ohio
Posts: 21,057
|
Have to be careful because there are several different AR chamber configurations available with differing freebore lengths. The same things may not be true for them all.
__________________
Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle |
November 6, 2013, 03:34 PM | #8 | |
Member
Join Date: March 4, 2013
Posts: 80
|
Quote:
|
|
November 6, 2013, 03:58 PM | #9 |
Senior Member
Join Date: January 10, 2012
Posts: 3,881
|
all the bullets I load for my AR's are pointed tips. Hornady soft point, Hornady FMJBT, Varmint extreme and varmint hollow point from Mid South Shooters. Also a Hornady 68 gr bthp. They are all pointed bullets.
|
Thread Tools | Search this Thread |
|
|