The Firing Line Forums

Go Back   The Firing Line Forums > The Skunkworks > Handloading, Reloading, and Bullet Casting

Reply
 
Thread Tools Search this Thread
Old October 31, 2010, 02:25 AM   #1
AK Shooter
Member
 
Join Date: September 26, 2007
Location: Anchorage Ak
Posts: 26
DPMS LR-260 issue

I finally sourced a new LR-260, NIB. I cycled a cartridge measuring at 2.800" (SAAMI max length for 260 Rem) and found that there were rifling marks on the bullet. I then verified with a OAL tool that the camber is measuring at 2.775".

After confirming this issue with DMPS, I was told to drop the upper assy in the mail for them to evaluate it. Additionally one of the mags had an inch long crack vertical down the backside, which was also returned. I'm not sure if the crack was caused by a back pressure problem at the time of test firing or not but it seems suspect.

I will be loading for this and knowing I could've made it work by seating the bullet a little further, I don't feel it is right. Hopefully it will be a quick evaluation and the will confirm/fix this in a timely manner.

Any thoughts?
AK Shooter is offline  
Old October 31, 2010, 03:38 AM   #2
HiBC
Senior Member
 
Join Date: November 13, 2006
Posts: 8,282
My wild guess.
Different bullets have different ogive profiles.I do not know what bullet you are using.
It might be when someone chooses a .260 they are thinking of longer ranges and higher BC bullets..As the VLD ish bullets are approached,the rifling needs to be closer.The general trend ;its harder to get good accuracy if VLD or skinny bullet has to jump.
What you have may be ideal for higher BC bullets.

If I load a 162 gr A-Max in my 7mmrem mag M-70 Laredo,the longest rounds I can fit in the mag box have to jump .150 to contact the rifling.I would prefer to have your problem.
HiBC is offline  
Old October 31, 2010, 06:58 AM   #3
geetarman
Senior Member
 
Join Date: November 18, 2009
Location: Arizona
Posts: 3,157
HiBC,

Quote:
The general trend ;its harder to get good accuracy if VLD or skinny bullet has to jump.

My experience with VLD bullets is quite different. I started out with them on the lands and accuracy was not so good.

In working up loads for my .308 bolt gun I did the following.

I loaded up 40 rounds with some on the lands, some -.040, some -.080 and some -.120 off the lands and found the -.040 and -.080 shot much better than the rest.

I then tweaked the load by loading up some more at -.045. -.055. -.065 and -.075 off the lands and found those at -.065 REALLY shot good.

I shoot a lot of .168 gr. Noslers and they shoot better about -.070 off the lands.

The rifle is a Remington 700P

Geetarman
geetarman is offline  
Old October 31, 2010, 07:10 AM   #4
Bud Helms
Senior Member
 
Join Date: December 31, 1999
Location: Middle Georgia, USA
Posts: 13,198
Quote:
My experience with VLD bullets is quite different. I started out with them on the lands and accuracy was not so good.
Not surprising. Type of bullet aside, I've never heard it recommended that a bullet be seated on the lands. The objective is to find that distance off the lands that is right for your chamber-bolt combination. 'Sounds like you did.

This belongs in Handloading & Reloading.

Moving ...
Bud Helms is offline  
Old October 31, 2010, 08:06 AM   #5
geetarman
Senior Member
 
Join Date: November 18, 2009
Location: Arizona
Posts: 3,157
Bud,

Berger recommends loading into the lands as a starting point. According to them, some rifles work just fine that way. I have found by visiting their web site, they have taken that advice down or I am looking in the wrong place.

They are getting ready to release load data for their bullets and it may be there.

I have not found that to be true. My experience tells me to load off the lands at some distance that you have to find on your own by experimenting.

The problem with some loads is that they must be shot one at a time.

I know Federal Trophy 168gr loads are set to feed in all magazines and the factory bullets shoot fine in all my .308s.

Seems to be that most loads set between -.065 and factory spec. OAL will work fine and both will load into my magazines.

I suspect that variance in my groups is me rather than the loads themselves.

Geetarman
geetarman is offline  
Old October 31, 2010, 11:28 AM   #6
AK Shooter
Member
 
Join Date: September 26, 2007
Location: Anchorage Ak
Posts: 26
For what its worth, the cartridge was a Sierra 140 gr match king. Every other rifle I load for the COL is limited by the magazine and proper feeding. With this 260, the cartridge will clear the mag but is too long for the chamber.

My pickle is that reloaded ammo will void DPMS's warranty. While factory ammo loaded by SAAMI standards will not function properly.

Last edited by AK Shooter; October 31, 2010 at 11:45 AM.
AK Shooter is offline  
Old October 31, 2010, 01:09 PM   #7
HiBC
Senior Member
 
Join Date: November 13, 2006
Posts: 8,282
I did not intend to recommend seating long enough to contact the lands.In a semi auto that would not be ideal.
Each rifle is a little different about what works.
HiBC is offline  
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 12:51 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2021 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent: thefiringline.com
Page generated in 0.04021 seconds with 10 queries