Barrel Swap

Cat 64 · 04-07-2014, 02:48 PM

I just finished building my 6 mm BR (Savage target action RBLP, CBI barrel and savage F Class stock) which by the way it is a wonderful caliber. Guys...you know how we are....always pursuing the next plateau of our performance, always wanting another gun added to our panoply. Well, not immune to that 'virus' I contemplated my next build. In general lines I realized I would like a somewhat a similar platform but with a 6.5mm bullet ( I am torn between 260 Rem and 6.5x47 Lapua). Gathering some advice on this forum I realized that perhaps I should, rather then build a whole new gun (with added expense), just buy a new barrel and swap between the two intermittently. My question and dilemma is: will changing the barrel frequently mess up anything with the headspacing. I took great care to accomplish a tight headspace (0.0015) and I am wondering if going back I will be able to maintain the exact same parameters. I mean all my dies, cases, modified case, etc, are set for my initial setup? I guess the bottom line question is ...Is it OK to change barrels frequently?

**Hotolds442** · 04-07-2014, 07:45 PM

I use index marks on my switch barrel rifle. The action has an index mark, as well as both ends of the barrel nut, and the barrels. I simply line up the marks and I'm good to go. It takes a couple of minutes extra to get all of the marks lined up, but I haven't had any issues. I keep an excel spreadsheet that looks exactly like my bore sighting collimator, with a seperate worksheet for each of my barrels, so I know exactly where to set the scope when finished. So far I've had better than 1/4" accuracy when switching barrels.

**jonbearman** · 04-08-2014, 12:53 AM

Explain how and where you put your index marks with a barrel nut.I am not being smart I really want to know and if you could post a pic of how you do it,it would be much appreciated.

KRP · 04-08-2014, 01:09 AM

I bought my first Savage with the thought of possibly switching barrels, which I did...but only once to get rid of the factory one. I just build new rifles and avoid any hassle. For a switch barrel rifle I'd get rid of the nut.

**Hotolds442** · 04-08-2014, 03:56 AM

Originally Posted by jonbearman

Explain how and where you put your index marks with a barrel nut.I am not being smart I really want to know and if you could post a pic of how you do it,it would be much appreciated.

I use a 3/16" "v" letter punch. At the action/barrel nut juncture the point of the "v" on top of the action faces the point of the "v" on the barrel nut. At the barrel nut/barrel juncture, same marks align the two. I'll try to remember to get pics when I get back home in a couple of days.

Cat 64 · 04-08-2014, 08:07 AM

Originally Posted by Hotolds442

I use a 3/16" "v" letter punch. At the action/barrel nut juncture the point of the "v" on top of the action faces the point of the "v" on the barrel nut. At the barrel nut/barrel juncture, same marks align the two. I'll try to remember to get pics when I get back home in a couple of days.

Thank you. That would really help to better visualize the process.

**BillPa** · 04-08-2014, 12:25 PM

You can also use modified gauges, a shortened NO GO for example to reduce the tolerance between it and the GO.

When I made my 204 gauges I purposely made the NO GO only .002" longer than the GO. One reason, that barrel may or may not go back on the same action so witness marks wouldn't be of any real value and two, I don't need to change my FL die setting. With the short NO GO I can set the chamber length within a .001" or less of the GO gauge length. If the bolt cannot the locked to battery on the short NO GO the chamber length must be something less than its length.

Another trick, check the headspace setting before removing a barrel with Plastigage. Put it on the boltface, chamber a case then compare it to the lines on the package. When you reinstall that barrel reset it using the same Plastigage measurement. The green (.001"-.003") will usually suffice. Its available at most auto parts stores.

Thank Sharpshooter for that trick.

Bill

**Upjeeper** · 05-05-2014, 09:48 PM

theoretically threads expand every time they're tightened. since the only threads your putting stress on are the barrel nut, i don't "think" it should be a problem. if you swap the barrels a lot you may find you need a new barrel nut.

do you index your reloads with a specified distance from the projo to the lands? you might find that changes