Savage barrel on a 308 MVP..... she works!!!

Discussion in '308/ 7.62 MVP and Variants' started by Al in Mi, Jul 16, 2016.

  1. Al in Mi Active Member

    Member Since:
    Nov 19, 2014
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    Making a switch barrel or rebarreling a 308 MVP has been bugging me since I first found this forum. 6.5 Creedmoor and a 45 Raptor really peaked my interest. Finally got caught up enough to get semi into it and here's what I found.

    1) Thanks to ole Billy Joe Bob's cousin Brutus, my factory barrel nut wouldn't budge no matter what I tried, although my pipe wrench had fairly well used teeth, nadda, so ended up giving it the ole Dremel slice treatment.

    2) barrel threads are 1.062 x 20............. imagine that, same as a Savage small shank, and before I get tossed under the ole bus on a Savage being 1.055 x 20, I checked the pitch diameters both barrels with a thread micrometer, and they are within .002 of each other ;)

    3) Took some wheeling and dealing and finally found a cheap Savage 243 barrel, screwed a factory Savage barrel nut on along with the MVP recoil lug, set headspace, made up some dummy rounds for a function check in a Pmag, all's good. :)

    4) Next up was live fire test out the back door and she works!!!

    Pic below show the factory 308 barrel along side the Savage. Both have the same flat faced breech and slight radiused chamber. Thread length on the Savage is 1.550 long , the MVP 1.730 long with a 1.175 shoulder. You could use the factory MVP nut on the Savage but there will be a gap over the barrel past the threads.

    Next pic is how it looks in the stock, plenty of free float, lol, and looks off centered, but just the angle of the pic. I would assume if one was looking to rebarrel or make a switch barrel rig, he'd contour it close to the factory anyways.

    So bottom line, a 308 case head sized small shank Savage barrel, can be a direct swap to get into a different caliber. This one was a 243, it fed and ejected fine from a 10rd Pmag which is what I had handy. I would assume a 6.5 Creed will too, dunno about the shorter 22-250, might need some tweaking.

    308 barrels.jpg





    View attachment 1739 View attachment 1739 308 mvp.jpg
  2. spamassassin Well-Known Member

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    That's really cool man. The savage barrel nut is an upgrade of its own. The factory Mossberg one just looks ugly as hell anyway. I predict a lot of switch barrels being made.
  3. Keith Moderator

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    Glad you were able to make it work. Now for. Stock or some filler to fill in the gap around the barrel.


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  4. wood chucker Moderator

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    Thank you Al !

    BTW just added this thread to the table in What Fits
  5. Al in Mi Active Member

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    yeah Keith she looks a little fugly with that sporter barrel. When time comes I'll probably have it contoured to match or there may be a profile close now.

    would like to see what a Boyd's stock looks like thou.
    Keith likes this.
  6. Shaun Member

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    I knocked my 308 apart a couple days ago and just tested it with a Savage take off as well. I was going to search to see if anybody had tried this yet. Nice of you guys to have it near the top.

    The distance from the front of the receiver to the end of the bolt is 0.735" on the Mossberg, it was 0.698" on the last Savage I worked on. The recess in the bolt face is ~0.114" on the Savages, its ~0.122" on my Mossberg.

    The upshot of that is the barrel tenon will have to be (0.735" - 0.698") + (0.122" - 0.114") = 0.045" deeper with the Savage barrel in the Mossberg action. That's about 1 turn. The end of the barrel will need to be 0.008" closer to the face of the bolt. They usually run 0.020 - 0.030" on the factory Savages, and gunsmiths leave them in the 0.005 - 0.010" range, so that should work out fine as well.

    Clocking of the lettering probably won't land right, but Savage prefit barrels should work as well.

    If I was going back with a barrel nut, the Savage looks like the way to go for length. I'm not though.

    Other interesting bits that became obvious when looking down the action with the barrel out were there isn't much lower lug in this thing between the thickness and the cut outs for the cartridge stripping projections, and the bolt lugs weren't bearing on the bolt lugs evenly. The bolt was grinding into the radius where the receiver wall transitioned to the lug abutments. I beveled the outer edge of the bolt where it was hitting the radius and it lapped in very quickly using 600 grit compound. I checked the squareness of the threads in the receiver by lapping the face using the factory barrel, recoil lug and nut. It cleaned up really fast with 600 grit as well. The threads are well machined and it doesn't look like there is enough at the front of the receiver to properly locate a truing mandrel. I'm not going to bother truing it.

    This one is going to become a 6xc because I already have the reamer. Keeping with the low buck theme of the gun, the blank is a chrome moly #7 Shilen I picked up on sale for $170. It's an 8 twist and I'll finish it at 26". I'll have to open up the varmint stock for it.
    jason.hayes3 likes this.
  7. gashmaster344 New Member

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    Dec 22, 2015
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    i wonder if any one has reset the headspace on their factory barrel. tight on a go guage just to see if they could squeeze out a lil more accuracy, and take the end play out of the bolt...
  8. GrocMax Active Member

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    Shaun- all 6XC reamers are not alike, verify if its the current Norma (243/308) brass base diameter or the original 22-250 case base diameter. While 22-250 cases will work, they don't contact the chamber for approx. .100" at the base due to the diameter difference (.466 vs .469ish), this can lead to some issues.

    Also most Savage drop-ins have at least one extra thread to work with if not two. Off the top of my head small shank is set up for 1.600" length of thread from most drop in barrel mfgs I've used. There could possibly be an issue with the difference in bolt head counter bore depth, most Savage drop ins are set to .115'-.120" and my 5.56 MVP bolt head counterbore measured at .125", so verify bolt head to barrel clearance, suggest .010" to .015" for gas to escape in case of a case rupture. The fix is to take about .010" off the chamber end of the barrel, then if you find the threads are a little short, instead of attempting to rethread, cut a short say .125" tenon at the end of the threads with an OD slightly under the minor thread diameter of the nut, end of nut should cover this cut.
  9. GrocMax Active Member

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    Over the last few years I've found more than a couple prefits the chamber was cut too deep, thus reducing bolt to barrel clearance so that either very little clearance exists or you're actually getting bolt to barrel contact before zero headspace. Highly recommend verifying this.
  10. Shaun Member

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    I compared a factory Savage barrel, which would be a really cheap swap.

    In the case of a Savage prefit, if whoever did the prefit closed up the bolt to barrel clearance to typical custom dimensions, there could very well be an interference before minimum headspace was reached. How straight forward that would be to resolve would be would depend on the hobbyist.

    The other problem in both cases will be the clocking of the chambering label. I seem to remember Tony swearing about random or multiple clockings with the 223 barrel. If the 308 has the same problem, it's a problem for even a true Mossberg 308MVP prefit.

    CIP body on the reamer, Norma Brass, not my first barrel chambered with the reamer. This one is set up with 8 thou from the barrel end to the bolt face. I used a standard 1.25" shank barrel blank, so no nut.

    6xc_ProgSmall.JPG

    Progress pic. Barrel is chambered, stock opened up, action and barrel are painted. I'm making it up as I go along and have time. It'll get the factory trigger and EGW 20moa rail again. I milled the action screw pillar flush with the stock and squared the front of the trigger guard to fit the Tromix 223 trigger guard. Didn't go with #8 screws on the rail so I'll probably pin it to the action. Not sure on the bedding or scope yet. I did a full bed of both the block in the stock and the action to the block on my 223 and am leaning that way. I have a Bushnell ERS 30mm 6-24 with the G2DMR reticle on another rifle and think it'd work well on this gun as well.
    jason.hayes3 likes this.
  11. GrocMax Active Member

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    Don't know on the 308 MVP but for the 556 the difference between avg bolt head counterbore depth is .010" MVP being .125" and the avg Savage .378 bolt head .115". It could be a problem for some, it was on my first barrel for the MVP, chamber was cut .010" too deep. Just something people need to be aware of.
  12. Al in Mi Active Member

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    if anybody wants some inside action measurement while I have mine apart, just holler.
  13. Shaun Member

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    The measurements that will determine if there is enough barrel to bolt clearance are the projection of the go gage from the back of the barrel and the bolt face recess. The difference between the 2 is the clearance between the back of the barrel and the bolt.

    BarrelClearance.JPG

    With this 308MVP, the bolt face is recessed 0.122". The go gage projects from the back of the Savage take off barrel 0.126", leaving a clearance of 0.004". Tight, but it works. Another Savage barrel was 0.132' on the gage projection, which would have given 0.010" clearance.

    Before we get too excited about all that, the MVP barrel had 0.124" of gage projection. OMG, the sky is falling, there isn't enough clearance! No, it's headspace was something above minimum for a 308, probably above a standard +004 NoGo gage. I didn't check it while it was assembled. The chamber isn't oversized until it's past a Field gage, which is the SAAMI max of +0.010". NoGo gages are a gunsmiths chambering tool, they don't have any significance as far as safety is concerned.

    If you have an interference, material will have to be removed from the back of the barrel. This isn't rocket science or brain surgery. If you have a lathe, use it. If not, it'd be a simple job to do neatly with a file. The truly bold and irreverent will use a grinder. The back of the barrel doesn't align anything, there just needs to be clearance.

    If the lettering on a Savage take off barrel lines up after head spacing it on a MVP, it'll be pure luck. This may or may not be a problem for you, but a supplier has obligations to provide legible markings. If there are problems with different clockings between MVP receivers, I'm wondering if labeling them past the end of the stock would solve the problem. I've seen AR barrels marked that way.

    I don't see the problem with using Savage take off barrels to do on the cheap caliber conversions.
  14. Bobby Kobito Member

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    Feb 1, 2016
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    If you want a Savage Barrel, then buy a Savage... Why go thru all the Hassle of Swapping Barrels out and Risking Damage to the Gun or more importantly yourself??? About the only reason, I can see wanting to swap a MVP Patrol Barrel in .308 is to increase the barrel to 20 or more inches for the FPS, while the shorter barrel is a couple of hundred fps slower and not as accurate! You bought the Patrol version because of the 16.5" barrel so why mess it up? Or if its a longer barrel you wanted then just buy the MVP Predator with a 24"...
    What is it with everyone today buying a Rifle and then changing everything about it? It just doesn't make any sense to me because you should be buying the Rifle you want in the 1st place, right? I have a Savage AXIS HB in .308 with a 22" barrel for longer shooting and my MVP Patrol in .308 16.5" barrel for shorter work.
  15. spamassassin Well-Known Member

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    C'mon Bob... Not everyone has a well stocked gunshop in proximity and quite a number of people impulse buy on guns, especially gun nuts like me. Sometimes you just decide you want to go another direction, sometimes you bought something because you wanted some of the features and planned on doing something else with it. Like the Prophet said, "It's my dog and my peanut butter." Don't need to understand or even condone what someone else does with their property. That's the best single thing about property. It's yours to do with what you please.

    I bought my MVP purely because it could take STANAG mags and that would make my annual squirrel slaughter a lot faster and more fun. I was right on that. The gun was such a good shooter though that I decided to use it in competition and quickly found faults with it being used like that and that required all kinds of changes to the stock, trigger, load, etc... I had to even stop using the mag for feeding in match shooting. Now I'm fixin'a make it a 6x45 and add .223 switch barrel (added .223 so I can stay in Tac-223 class for Long Range Precision matches). I've just about worn out my factory barrel.

    I got my .308 Savage 10FPSR with the express intention of making it a switch barrel .308/7mm-08 that will almost never use the .308 barrel. Could have just gotten a 7mm08 rifle right? But no. I had an opportunity to swap into the .308 and buy a barrel for it in 7mm-08 later. I could have started off with a 10BA but I built myself the equivalent of the new Savage Stealth instead.

    Now then... where's my dog and my peanut butter?
  16. Keith Moderator

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    Some people on here like to be able to swap barrels for different calibers out of the same rifle. Others second guess their original purchase and want to minimize the expense to get what they want. And others just like to tinker and enjoy the challenge.

    To each their own. I was able to (mostly) get the rifles I wanted from from my LGS but not everyone is that lucky. Some places have to go a fair distance just to get to a gun shop, good or not. I'm fortunate that I have several withing a 20-30 minute drive.
  17. dashaw New Member

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  18. Keith Moderator

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    I'm confused by you post. Was there some commentary supposed to be with this?


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  19. boostless Active Member

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    I think he was asking what barrel brand he went with.
  20. dashaw New Member

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    I had asked what brand barrel he used

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