Go Back   Maryland Shooters > The Arsenal > Rifles
Don't Have An Account? Register Here

Join MD Shooters

Reply
 
Thread Tools Display Modes
Old May 22nd, 2020, 12:32 PM #1
DavidA's Avatar
DavidA DavidA is offline
The Master of Disaster
 
Join Date: Dec 2013
Location: Annapolis
Posts: 167
Send a message via Skype™ to DavidA
DavidA DavidA is offline
The Master of Disaster
DavidA's Avatar
 
Join Date: Dec 2013
Location: Annapolis
Posts: 167
Send a message via Skype™ to DavidA
260 Remington in long action R700

So I have three Remage R700 rifle one in 270 win with a 1-8 twist barrel. One 284 win 1-8 twist and one 338 win Mag. So I am buying a Black Hole Weaponry 26” barrel that I can switch out with one of the Standard .473 long actions. I know I could do 6.5 x 55 Swede or a 6.5-06 . I get it. I just have a two LR308’s in 260 Rem and they shout great. I just wanted to pull 260 Rem over to a bolt gun, as I have all the match dies and components already for 260 Rem. The object is to load the bolt gun rounds as long as I can to get the best performance out of the cartridge. My calculations say I should be able to load Hornady 147 gr RLD M bullets to a COAL of 3.05” +/-. So beyond SAMMI by a ways. Any hoot I have enquired Columbia River Arms about what the free-bore is on the readers they are using and to see if they will match them to dummy rounds if I send them. No answer yet. But if they will not what are my options to extend the free bore to match the intent of my rifle? Also while I have read that feeding may not be a problem, what modifications if any do you think will be required to magazine. Magpul bottom metal with their 10 round magazines.


Sent from my iPhone using Tapatalk
DavidA is offline   Reply With Quote
Old May 22nd, 2020, 12:41 PM #2
dedan dedan is offline
Junior Member
 
Join Date: Dec 2011
Location: delaware
Posts: 22
dedan dedan is offline
Junior Member
 
Join Date: Dec 2011
Location: delaware
Posts: 22
most rem 700's, 260, 7-o8, are on short actions. longer bullet you might feed it single shot. also, if you do 260, barrel should be 1x8, to shoot heaver bullets. remington 260 barrels are 1x8 1/2, not great for heavy bullets....dan
dedan is offline   Reply With Quote
Old May 22nd, 2020, 01:00 PM #3
atblis atblis is offline
Senior Member
 
Join Date: May 2010
Posts: 1,345
atblis atblis is offline
Senior Member
 
Join Date: May 2010
Posts: 1,345
If you do have feeding issues, which I doubt, a single stack detachable mag setup should take care if that. There are a few to choose from. Magpul would not be my first choice.

Long 260 had been done. I suggest checking out 6mmbr.com

http://forum.accurateshooter.com/thr...pment.3831912/
atblis is offline   Reply With Quote
Old May 22nd, 2020, 08:34 PM #4
DavidA's Avatar
DavidA DavidA is offline
The Master of Disaster
 
Join Date: Dec 2013
Location: Annapolis
Posts: 167
Send a message via Skype™ to DavidA
DavidA DavidA is offline
The Master of Disaster
DavidA's Avatar
 
Join Date: Dec 2013
Location: Annapolis
Posts: 167
Send a message via Skype™ to DavidA
Quote:
Originally Posted by atblis View Post
If you do have feeding issues, which I doubt, a single stack detachable mag setup should take care if that. There are a few to choose from. Magpul would not be my first choice.

Long 260 had been done. I suggest checking out 6mmbr.com

http://forum.accurateshooter.com/thr...pment.3831912/
Thanks I figured it should feed in a single stack no problems. Just waiting for the gremlins to come out since I am not not building a standard configuration. FYI got hold of Columbia River Arms (manufacturer of BHW barrels) The have a SAMMI chanber reamer and a Bore Rider reamer as well, So I just have to tell them how much beyond SAMMI do I want to extend the throat. Good news! Figuring it out with bullets will talk some research. Ill be checking out that atrticle now. Thanks
DavidA is offline   Reply With Quote
Old May 22nd, 2020, 09:06 PM #5
Doco Overboard's Avatar
Doco Overboard Doco Overboard is offline
Senior Member
 
Join Date: Jul 2016
Location: The heart of the Delmarva Penninsula
Posts: 3,448
Doco Overboard Doco Overboard is offline
Senior Member
Doco Overboard's Avatar
 
Join Date: Jul 2016
Location: The heart of the Delmarva Penninsula
Posts: 3,448
Id get it short so when it becomes worn or you want it adjusted you could re-cut the throat only.
Doco Overboard is offline   Reply With Quote
Old May 23rd, 2020, 08:35 AM #6
DavidA's Avatar
DavidA DavidA is offline
The Master of Disaster
 
Join Date: Dec 2013
Location: Annapolis
Posts: 167
Send a message via Skype™ to DavidA
DavidA DavidA is offline
The Master of Disaster
DavidA's Avatar
 
Join Date: Dec 2013
Location: Annapolis
Posts: 167
Send a message via Skype™ to DavidA
That is a good point. You can’t add throat back in. So of course this got me thinking. So it called for a spreadsheet to analyze SAMMI spec chamber dimensions and where different bullet would be at the lands. So based upon SAMMI chambers specs, a Hornady 147 gr ELD M will HITT the lands at a COAL of 2.916” bases upon my 260 new unfired brass 2.025. It comes down to a .553 case intrusion. Optimum intrusion is roughly .400. In a SAMMI chamber free bore is .1185 and the lead is .0859 so total throat is .2044. So if you pushed it out .15 you would have a COAL of 3.066 to lands and a case intrusion of .3894. If you set back 10 thousandths back .01 you would have intrusion of .3994. Dam near perfect. So I went on the compare other long heavy bullets with a extended .15 bore total throat of .3544

Berger 153.5 Hybrid target calculated out to 3.1176 COAL at lands with .4204 intrusion.

Nosler 140 RDF calculated out to 3.078 COAL .3659 intrusion. bearing surface in knock in this case is a littler short.

Berger 156 Elite Hunter calculated to 3.1326” with intrusion of .4034.

Sierra 150 SMK calculated 3.1376” with intrusion of .3734.

All of the above would work to the lands but this is the max length load with bullets at lands. Chances are I will not jam lands as they erode the throat faster. So if I go back 10 thousandths these will be fine extending the throat .15 from SAMMI. I do want to preserve some dimensional spacing though for chasing the lands as the throat moves. So I am thinking .12 or .13 extension. With the above bullets at lands COAL range 3.036 to 3.107. I could push it to a .15 extension but that is max today. Any hoot. Here is link to the spreadsheet if you have any interest. With Reloader 26 I am thinking 2850 fps with 150 SMK bullets . That’s would place it supersonic to 1800 yds at sea level. with a 10 degree cross wind at sea level and 200 yds zero. at 1,000 yds 7.0 mil drop , 1.39 mil drift.

https://1drv.ms/x/s!Am5F-6DkWN6fgaIc8Bk86zsoivhThw


Sent from my iPad using Tapatalk
DavidA is offline   Reply With Quote
Reply

  Home Page > Forum List > The Arsenal > Rifles


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

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 -4. The time now is 01:39 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
© 2019, Congregate Media, LP Privacy Policy Terms of Service