Help me customize my M70

[Gtscotty]

So I really like the Winchester M70 action, and decided recently that I was going to sell one of my M70's to fund a project to customize the other one. By customize, I really only mean a new barrel and stock. Before I started placing orders I figured I would bounce some ideas off of THR members to try and tap into the collective experience.

The first thing I'm going to order is a new barrel. The rifle being customized is an FN Winchester M70 Featherweight in .243 win. The rifle shoots great as is, but that's not the point, I want to build a one-off from this already excellent starting point that I will keep long term. I'm not worried about resale value as the rifle will not be sold.

The desired end product is a relatively short/handy/light weight rifle for up to 350 yd deer/antelope hunting and maybe 200 yd elk. 90% of this rifle's use will be for carrying around in the mountains while chasing deer, realistically, I have a 30-06 that will be used for most of my Elk hunting. I was originally looking at 6.5 Creedmoor, but have since more or less settled on .308 due to it's all around utility, availability, ease of loading, and the fact that I already have, and load for two other .308's. The only possible wild card is 7mm-08, I've never loaded for it, or even shot one but it is kind of intriguing, if anyone has any compelling reasons why it would be superior to .308 for this project, I'd be interested in hearing them.

As for the barrel maker, I don't have a local smith that I trust for something like this, so I have more or less restricted my potential barrel manufacturers to those that will also contour, chamber and re-barrel my action (most will square the action and lap the lugs while they are at it). As far as I can tell, my list of barrel makers that offer re-barreling services includes Douglas, McGowen, Pac Nor and Hart. Of those I am leaning towards Pac Nor as they have a good reputation, run about $100 less than Hart and took the time to answer questions when I called. I'm very interested in THR's recommendations on these barrel companies, as I don't have any first hand experience with any of them.

As for the Barrel itself, assuming I go with .308, I was tentatively planning on keeping the featherweight barrel profile to keep weight down and ensure that the barrel fit's whichever stock I wind up with. I considered barrel lengths from 18" - 22", but have kind of settled on 20" as a good balance of compactness, lightweight, retained muzzle velocity and muzzle blast. I thought about splitting the difference between 20" and 22" and getting a 21" barrel, but a few velocity vs barrel length test I found on the web don't seem to show a much difference in MV between the 20" and 22", and the 20" and 21" were within single digits of each other. Again, all of those thoughts are centered on the .308, if I went with 7mm-08, or 6.5 CM, I would need to re-evaluate.

So what, in particular, would you do if you were trying to build a rifle similar to the one I described? Experiences and opinions welcome.

 

[cprher]

How about 260? Doesn't kick the snot out of you like a featherweight 308 will, shoots flatter than a 308 and is renowned for its accuracy. McMillan has a line of lightweight stocks made with carbon fiber, Kevlar and fiberglass. Light but very strong. Since the cartridges you are interested in don't kick like magnums, a simple but light foam fill is all you need with the right outer skin. Sound like a fun project.

Keith

 

[jmr40]

Can't help with a barrel maker, but I like the 308. Since you already have a 30-06 it helps with only stocking one caliber of bullets that can bee used in both. A 7-08 or 260 is also an option and since 308 and 30-06 are so similar in performance going down to a smaller caliber on the 2nd rifle has some merit. Having similar rifles in the same caliber has merit too, build one heavy, the other light. Problem with that is that once you get used to the lighter rifle you'll never go back to the heavy one.

The 308 will still work as an elk, gun loaded with 200 gr Accubonds it holds 1500 ft lbs of energy to almost 500 yards. I think 21" is a decent compromise on a custom. I like the length, but it isn't worth cutting 1" off mine as is. If it had started at 24" or longer I'd have had it cut to 21".

I wouldn't consider anything but a McMillan Edge. They offer several different styles but I think the Compact Classic looks best on that rifle. Don't consider anything but the Edge made of kevlar. It is 1/2 lb lighter than the standard stocks and comes standard with aluminum pillars that will cost extra on the others. Well worth the small price increase. Compared to your 30-06 recoil will still be noticeably less even though it will be lighter.

Here is what I did. I bought a used 308 Winchester EW several years ago. I used it as is for 1 year before I found a used McMillan Edge stock at a good price. I had some PT&G aluminum bottom metal left from another project that I used. It only saved about 2 oz. over factory. It is about 6 oz lighter than the steel bottom metal used on some guns. It didn't help much on the EW and I wouldn't spend the money to save 2 oz (6oz, yes), but since I already had it I used it. Total weight including the 3-9X40 VX-2 and Talley mounts is 7 lbs 5 oz.



That is about as light as you can get a Winchester without serious modifications. I also have a Kimber 308 that comes in at exactly 6 lbs with the same scope. I like the Kimber, but the EW is the one used most. Not too heavy to carry, not too light to shoot easily. Mine is a shooter, just about any bullet or bullet weight will produce 3 shot groups of .5-.75 MOA

This is typical accuracy

 

[MrBorland]

The desired end product is a relatively short/handy/light weight rifle for up to 350 yd deer/antelope hunting and maybe 200 yd elk. 90% of this rifle's use will be for carrying around in the mountains while chasing deer, realistically, I have a 30-06 that will be used for most of my Elk hunting.

...The only possible wild card is 7mm-08, I've never loaded for it, or even shot one but it is kind of intriguing, if anyone has any compelling reasons why it would be superior to .308 for this project, I'd be interested in hearing them.

I don't have anything intelligent to add about barrels, but I'd say you ought to give serious consideration to the 7mm-08, especially since you've got a .30-06.

If you type some data into ballistic calculators, you might find that the 7mm-08 stacks up very favorably to the .308 for what you're wanting, and does so with less recoil. When I did the same, it told me that to 300 yards, a good 140gr bullet (e.g. Accubond) from a 7mm-08 will shoot a bit flatter, with drift less and deliver a bit more energy than a 165gr or 180gr .308 bullet.

 

[OldBrownDog]

I'm with jmr40 on the stock. McMillan EDGE fill in pattern of your choice.

And I'd also vote for 7mm-08. Besides ballistic advantages, I've found that different rifles in the same chambering/bore diameter often 'like' different loads or projectiles and become just as much of a pain as rifles in different chamberings/bore diameters because you have to stock separate components for each.

 

[CB900F]

Gtscotty;

In my opinion, if you have a .30-06 you need a .308 about like you need to take up dropping bowling balls on your foot for fun and profit. That being said, the 7mm/08 option isn't a bad one, but here's another one; the 6mm Remington. Whereas the .243 is a .308 based case, the 6mm is based on the 7 x 57 Mauser. This means higher velocities with heavier bullets of the same diameter.

I would certainly check to make sure the FN action will allow the 6mm to function in the magazine properly though. I know either the pre-64 or USRAC Classic Winchester actions would do so without a problem. If the action is not a true short action, then also consider the 6.5 x 55mm Swedish Mauser.

900F

 

[Gtscotty]

Thanks for all the input thus far. On the topic of which caliber would be the best choice for this project, I agree that .260 Rem is worth a look, and I've been reading a little on the cartridge. I originally was interested in the 6.5 Creedmoor because it seemed like an increasingly popular (read: available) chambering that offers high BC bullets with low recoil and good performance on game. The .260 Rem has all of these attributes as well, and would be an equally strong choice in a bolt gun. I guess what was pushing me towards .308, was that after reloading for a several years, playing ballistics calculations and tables and shooting game with a variety of calibers, I've come to the soft conclusion that most of the mainstream mid-size game hunting cartridges will do pretty much the same thing on deer sized game out to any range where I'm comfortable pulling the trigger. In light of that revelation it's hard for me to ignore the fact that I already have a couple of other .308's (M&P-10 and Tikka CTR) and find the cartridge very easy to load for (just like its big brother the '06)... in addition, it's the only big game cartridge that I've been able to pick up lots of used brass at the range for lately. All of that said, I still find the 6.5's 7mm-08 intriguing, so the decision is far from made. Do those of you who have loaded the 7mm-08 find it to be an easy round to find accurate loads for?

As for stocks, I had honestly been looking primarily at the newer B&C Ultra-light stocks, High Tech specialties stocks, and Manners. I know a lot of folks don't like the thicker wrists of the B&C, but I had a M70 EW at one time, and was pretty pleased with the stock overall. The High Tech specialties stocks have good reviews, and I was leaning in that direction, but a closer inspection of their website leads me to believe that their stocks don't come painted and require quite a bit of fitting. I'm counting on doing a skim bedding job, but I'm a little nervous about doing a whole lot of grinding on a fancy new stock. It sounds like the McMillan edge is well recommended, I'll have to do a little reading on it.

Jmr40,

Your rifle is a lot like what I'm going for, except with a shorter non fluted barrel, and, of course my Featherweight's receiver will still be blued. I'm really not going for super light weight so much as relatively light weight and handy, your 7.5 lb EW seems like it would be a good balance of shootability and portability. Out of curiosity, where did you find your used McMillan edge for sale?

CB900f,

My rifle is a short action, I don't know if the 7x57 or 6.5x55 will fit. Either way, I've been down the 6.5x55 road before, and couldn't ever get the velocities I was looking for. If I get another 6.5 it will be one of the more modern iterations, with lots of up to date, full pressure load data available. Similarly, if I went with a 7mm, I'd rather go for the newer 7mm-08 than the 7x57.

 

[Gtscotty]

Also, I'm curious to hear what kind of rifling twist/type people favor. For example, with the .308, Pac-Nor offers 2 - 6 groove traditional style rifling, and also polygonal rifling. The two most popular rifling specs seem to be 1 in 10" and 1 in 12" 5 groove, is there a big benefit to either? I've heard good things about hammer forged polygonal rifling, but does polygonal rifling formed with buttons, like the type Pac-Nor offers confer the same benefits (e.g.~ extended barrel life and increased muzzle velocity)?

 

[Gtscotty]

So after yall got me thinking about .260 Rem and 7mm-08 again, I decided that I should actually run some numbers to help me decide instead of just trying to "feel it out". The charts below show velocity, kinetic energy, trajectory (250 yd zero) and wind drift (15 mph full value cross wind). Velocity is in fps, energy is in ft-lb, and trajectory and wind drift are in inches.

I settled on a lighter and heavier weight bullet in each caliber, and used SST's across the board to try and make things simpler and more uniform. Also, the SST is one of the slickest bullets in any of these calibers that I'm likely to actually use for hunting.

Velocities are taken from Hodgdon load data, and then guestimated down to account for 22in barrels on the 6.5 and 7mm and a 20in barrel on the .308. The Hornady ballistic calculator was used to arrive at all of these numbers (BC's taken from manufacture data).

I also injected my 30-06 loads into the calculations, just for comparison's sake.









I actually plotted charts for all of these metrics, but the dots and lines were so close together they didn't really show much.

I think it is interesting that the max trajectory spread at 350 yds is just 1.9 inches, which, for my purposes is negligible. The difference in wind drift is a little more prominent with a 3.7 inch spread at 350 yds... Is that enough to sway a chambering decision one way or the other? Probably not for me.

I have to say, the 7mm-08 seems to do a good job of delivering most of the energy of the .308 with better external ballistics and likely lower recoil. Is it enough of a difference to justify 2 extra inches of barrel, and adding a new caliber to the stable?

 

[MrBorland]

I have to say, the 7mm-08 seems to do a good job of delivering most of the energy of the .308 with better external ballistics and likely lower recoil.

Told'ja.

As far as .260 Remington vs 7mm-08, I have one of each. I love the .260, but I think the 7mm-08 would be the better choice if elk are on the menu. It's just really hard to beat the balance of the 7mm-08.

 

[Sunray]

"...settled on .308..." Virtually the same thing as .30-06. The 7mm/08 is just a necked down .308. Don't think it has any real advantages or disadvantages other than maybe not being readily available in small places.
You really need to decide how much money you want to spend first.

 

[Gtscotty]

You really need to decide how much money you want to spend first.

I already know how much I'm willing to spend, $600-$700 on the barrel/re-barreling and $300-$400 (Maybe stretched to $500) on the stock/bedding. But that doesn't have any bearing on caliber choice, twist choice, barrel length or # of grooves as I already know that Pac-Nor will charge $605 to rebarrel any of these short action calibers to my specifications, and Hart will do the same for ~$700.

Told'ja.

Yep, it's an interesting caliber, might be worth giving a try.

Out of curiosity, are my projected velocity numbers in the ball park of what you're seeing with your 7mm-08 and .260? Also, I believe your .260 has a 20" barrel, what kind of velocities are you seeing with 120gr and 140gr?

 

[MrBorland]

Out of curiosity, are my projected velocity numbers in the ball park of what you're seeing with your 7mm-08 and .260? Also, I believe your .260 has a 20" barrel, what kind of velocities are you seeing with 120gr and 140gr?

I've only shot 140 SMKs from my CTR in .260 Remington. As you know (since you've got one, too), it's got a 20" barrel, and they chrono at 2550fps. A friend of mine bought some Black Hills match .260 ammo that uses a 139 gr Lapua Scenar, and they chrono'd at 2560 fps, just 10fps faster, so my loads are in the right ballpark. From a 26" barrel, I'd guess they'd pick up 180 - 200fps. Your 2900 fps seems optimistic to me, then.

As far as my 7mm-08 (by coincidence, a custom M70, though bought on GB), I haven't done much load development with it, though I've got a number of bullets to try out. Right now, my whitetail load is a 120gr Nosler BT, and it chronos from a 22" barrel at 2975fps. According to the Hornady manual, you'll drop about 200fps going from a 120gr to a 139gr bullet and another 100 going to the 154s - if so, I'd expect 2800ish and 2700ish with the 139s and 154s, respectively, then, which is what you predicted.