Retaining OAL/Headspace on barrel after swap

[DennisH87]

I just had a bright idea. I'm swapping barrels, 22-250 to .223. I want to keep the headspace and jam length the same on my .22-250 barrel so when I reinstall it the loads that I have worked up still shoot the same. So I figured why don't I seat a bullet to the jam length for each different bullet and then all I'd have to do is chamber the round with the bolt closed and screw the barrel down onto it until it stops, which would be when the bullet touches the rifling. I've never swapped a barrel before, Mine is still in the mail, so I'm not sure if this will work but its an idea. Now here's the question. For all you people with experience in changing barrels, would this work and if no why not?

[jo191145]

Best method is buy an extra barrel nut and locktite it in place. The nut stays on the barrel and acts as a permenent shoulder.

[bpratl]

Great idea....thanks.

[RWO]

Dennis87, it won't work. The barrel won't stop when the bullet hits the lands. The engagement is a very gradual slope and you can probably make at least 1/2 a turn before the lands dig in enough where you will notice the increased friction by which point the bullet will be forced back into the case and the case will have hit the chamber shoulder.

There is no substitute for a headspace gauge when changing a barrel. A simple OAL gauge like the Hornady will make it easy to determine seating depth for any bullet and a micrometer seating die will make correct seating bullet easy to set.


If you Loctite the barrel nut, you have thrown away one of the major features of the Savage action which is ease of swapping barrels. You will then need a full blown barrel vise and receiver wrench, same as any other bolt action to change a barrel and you have lost adjustability of head space as the threads wear.

RWO

[gotcha]

Dennis87, I agree w/ RWO! Pretty much the same answer I gave you to your post under SAVAGE BOLT ACTION CENTER FIRE forum pg.#2. Slow down, take a deeeeep breath, relaaaax. I answered one of the several questions you posed there to try and keep my post from being too long. In time, others will probably answer the rest of your questions. Good luck!

[DennisH87]

I know this is no substitute for a go no go gauge, just a check to see if it's set back to the original specs. now i understand ur right about the seated bullet being pushed back into case, but what about seating a plug thsts made for checking the throat length. i believe thats the right term. it's a steel plug thats seated then chambered and measured to make sure your case necks aren't too long. if i drilled the primer pocket out and filled it with epoxy that plug would be perminately set to the lands. after setting headspace w/ no go gauge insert the "custom gauge" and screw the barrel down on that. then recheck w/ go/no go gauge. i'm just brainstorming and want to know what u guys think since i have no exprience with this. i think this would effectively work as a set to gauge.

sorry for the sloppy post but i'm on my cell phone and i hate typing on this thing.

[Got Diesel]

Why not just put an indexing
mark on your action and barrel. Then either count the revolutions while removing the action or take a file and remove part of a thread on the barrel at that indexing mark. Then you would return to the exact spot time after time.

[hotbrass]

Why not get a go gauge and do it right? ???

[DennisH87]

Got diesel I think that wouldn't be accurate enough. It'll get you in the ball park but not the degree of accuracy I'm looking for. Hotbrass you don't understand or didn't read the entire post. I've got a Go gauge. And a No go gauge. I want to make a gauge that is exactly at the current headspace on my rifle so when I switch the barrel back I can reset it to the current dimensions.... Do a little reading next time before posting.

[BillPa]

I've got a Go gauge. And a No go gauge. I want to make a gauge that is exactly at the current headspace on my rifle so when I switch the barrel back I can reset it to the current dimensions.


What your searching for is quite simple.

One, make a set of gages to your spec. Here are the gages I made for the 204.
http://i41.tinypic.com/2vlmln5.jpg

I'd have to remeasure them, but IIRC they're 1.700"/1.702" on a .330" datum. With only a .002" difference it means I can and have reinstalled my 204 barrels to within 001" or less of it's previous setting.

Another way, shorten a NO GO. The typical difference between gage lengths is .003" to .006" depending on the cartridge. For 222 Rem its .003", for the '06 family, .006". With that small difference a NO GO is easily shortened for only a .002" longer length than the GO.

Next, shim a GO gage with a shim of a known thickness.

And last, more time consuming however, use Plastigage. Place a piece on the shoulder of a GO gage and/or a piece of brass with a known length then adjust the headspace until the plastigage indicates the correct amount of clearance.

Another option, have a set of custom gages made. PTG, Manson and possibility some others could easily make them to you specifications. At one time Dave(PTG) made a universal adjustable gage. You could check to see if its still available. Of course it wouldn't the too difficult making such an animal.

One thing to remember. The differences in gage lengths are ......
GO - Used to set the chamber "EQUAL TO or GREATER THAN" .
NO GO - Used to set the chamber "LESS THAN".

Using the 308 Win for example the GO length is 1.630", the NO GO, 1.634". If the bolt closes on the GO, the chamber must be equal to or greater than the GO gage length. If the bolt does not close on the NO GO, the chamber length must be something shorter than 1.634", 1.633" or less. Shortening that to only .002" difference now the chamber can be set to => 1.630", < 1.632", somewhere between 1.630" to 1.631".

The closer those tolerance are the more precise you can reset a barrel.

Resetting a barrel to a previous chamber length isn&#39;t hard. It just takes a consistent method and how you use the tools doing it.

Bill

[hotbrass]

Hotbrass you don&#39;t understand or didn&#39;t read the entire post. I&#39;ve got a Go gauge. And a No go gauge. I want to make a gauge that is exactly at the current headspace on my rifle so when I switch the barrel back I can reset it to the current dimensions.... Do a little reading next time before posting.


I have read it, and I understand. And you dont say you have the guages, you just talk about the process. You want to maintain the OAL you have currently set up, and you want to do that with the same headspace, right? If it is out of "spec" then you must have a gauge made, or make it yourself, but you already know that.

If it were me, determine the bullet setback you have established, I would keep the headspace in spec with a go gauge, and set the OAL of the bullet seater with the same bullet setback dimension that you established. You will have headspace in spec, and you will have the bullet setback from the lands the same distance as before. I dont think OAL is as important as the freebore between the bullet ogive and the lands. But you do it however you want.

Carry on.

[DennisH87]

billpa: thats exactly what i want to do but i don&#39;t own a lathe. i can probably use the one at work but don&#39;t know how to use it that well. great idea though.

[gotcha]

Dennis87, o.k. you&#39;re getting some pretty good ideas here but, you don&#39;t need machine shop to achieve your goal. Found a great post to answer ALMOST all your questions. VIDEOS TOO!! Go to bolt action center fire forum. ****** author: possum1 topic: head space posted: 1/19/10. Read it all as well as a companion thread and video. You will then be better informed than some who have answered your post including me!!! This site has some amazing info available if you take the time to search. I&#39;ve seen two of the three videos posted in the past but couldn&#39;t remember where. Let me know how you liked the info!!