Expected accuracy of featherweight contour

[greenejc]

You should be able to get sub MOA accuracy. My factory M70 EW in 30-06, which I'm told is an inefficient and inaccurate design, will group under an inch for 3 shots very easily with kibble it likes.

The -06 isn't inefficient, it just was loaded with powders that were 'fast' for the cartridge originally. It got a reputation for being less accurate than the .308Win due to the powders available for it in the first 45 years of its existence. I get less than 1" groups out of it at 100 yards with 180 grain Sierra and Speer bullets in three rifles, and less than 0.4" groups in a heavy barrelled rifle. I shoot IMR4350 and 4831, and am experimenting with Superformance for 200 grain bullets. But off subject. What is the difference between the .308 Win and the Bisley? Is it similar to an Ackley Improved? Also, you have a 1 in 11" twist so I wouldn't go higher than a 180 grain bullet, and I wouldn't use any of the long for caliber bullets in any weight. If the bullet is long for its weight it might not stabilize in a 1 in 11 twist barrel. I know these guys (some of them) are going to say mono and such, but try Sierra 165 and 180 grain Gamekings. Also try Nosler Ballistic Tips in 165, 168 and 180 grain weights, and Speer 165 and 180's. I get extremely good accuracy with these bullets out of all my .30 cal cartridges, in the 1 in 10" twist barrels my rifles have, and they're all high BC bullets for standard copper jacketed lead. Also, try RL 15 in your rifle. You're using a light weight barrel, so something you might try also is to shoot two 3 shot groups with everything the same and shoot at the same aim point to see how they overlap. Let the rifle cool between groups, and mark the two cold barrel shots. Keep in mind however, that a 1" or tighter group is a very good group in a light barrelled rifle, and if it will print under 3" at 300, its a good load for a .308Win. I've suggested shooting at 300yds because some bullets won't completely stabilize at 100 yards but will be on rails by 300. You will have to decide what is acceptable accuracy for this light rifle, but remember that perfect really is the enemy of good enough.

 

[PartsJr.]

Nice rifle.
I have the same model except in .270 win and is walnut and blued factory rifle purchased in 1983.
I glass bedded mine. With hand loads I can get sub MOA usually around 3/4" @ 100 yards and 4" give or take a little out at 400 yards.
With a custom barrel and the work that's been done, I would think you should get sub MOA as well.
Lots of good advice so far. Good luck.

 

[greenejc]

My. Go to deer. Rifle is a. Weatherby Ultralight rifle. 24. Inch. Krieger flutted S/S barrel,in270. Win! Thin barrel ,550 at the. Muzzle'
10. Or 12. Years ago. I could. Make. One. Hole. Groups at 100. Yards if I. Let the. Barrel. Cool! Now. At 73. I'm. Happy. With 1 And1/4. Groups! I. Learned. Shot. 1.and shot 2. Are. Usually. Fine but. I. Give the. Barrel 1 min. And 15. Seconds. Fir. Shot. 3. And. 1 min snd 40 seconds for all. Shots after. That ! I. Must. Say. Most of my deer are. Shot snd. Killed. With. The. First shot. ,two needed a. Second shot ,never. Fired. A. Third shot ! For Me. Light weight. Thin barrel , let it. Cool

1 1/4" groups are good groups for a feather weight or ultralight. My Ruger M77MKII has a .550" barrel at the muzzle, and I've gotten it down to consistent 0.8 to 1" 5 shot groups (4.5 to 5.5" at 500yds) with Sierra, Speer and Nosler 180 grain bullets. My 1903-A3 with a military contour shoots noticibly tighter with the same loads. These are both 30-06 cal. I have a varmint contour Remington SPS in .308Win and a H&K in 7.62X51 Nato which I also load for. The H&K will go inside 1.5", and the Remington is a 0.5" rifle. My brother and I had a 30-06 made on a small ring Mauser '98 action with a 20" full bull barrel from ER Shaw about 19 years ago, and I get 2630fps with IMR4350 and around 0.3 to 0.4" 5 shot groups out of it with Sierra, Speer and Nosler bullets in 165 to 180 grain weights. Barrel thickness (stiffness) makes a real difference.

 

[cabelasken]

I have two 7-08s , one a model 7 and the other a remington titanium. Both now have 22" Pac-nor barrels with an ultra light contour. Neither have been consistent 1 MOA groupers, but I found a vibration donut placed about 2-3" ahead of the end of the stock helped some. Both guns have free floated barrels. After 5-600 rounds thru each, I am stuck at about 1 MOA, so, no I haven't yet found the sweet spot. But, It's a challenge that I welcome.

 

[emp1953]

Do you shoot from the magazine or feed one round at a time manually? I have a SIG 970SHR in .270win and a M70 featherweight in .270win. I shoot 150gr NPT's at around 2950fps. In the SIG get consistent 0.6" groups. In the M70 I get 0.8" groups if I manually feed the rounds, not using the magazine. If I use 4 in the magazine and 1 in the chamber in the M70, the first shot goes exactly where I want it, each subsequent shot walks off to the right just like your targets show. I did a test where I measured the COAL between shots and found the COAL decreased by .002 - .004 per shot. By the time I got to #5 my round was .020" shorter than when I started. Recoil isn't an issue in the SIG because the rifle/scope combo is heavier than the M70. Recoil is more pronounced in the M70. Bullets are being forced against the front of the magazine with each shot, being pushed further into the case creating a shorter COAL with each shot. I was able to correct it by putting a tiny bit of crimp on the case. But that changed my grouping so I started annealing my cases. I can now shoot from the magazine without the horizontal stringing and am back under an inch. Also I don't shoot a 5 shot group any more unless I take 15 minutes for the 5 shot string. I stick to 3 shot groups and still allow a lot of cool down time between shots. Its one of the "consequences" of wanting an ultra-light rig with a pencil thin barrel. It's no less accurate, but it is definitely a hunting rifle, not a target/benchrest rifle.

 

[nwhunter]

I have owned a 1/2 dozen of the earlier 80's era Winchester featherweights, running from 257 Roberts through 30/06.
I still have the 257 and a 7x57. The only one that shoots considerably better than your rifle is the 257, it seems to throw about any load I try at 3/4" or less at 100 yards. The 7x57 shoots about with your rifle at 100 yards. I always shoot 3 shot groups.
Even though the 257 shoots lights out at 100 yards it opens up at longer distances to unacceptable groups beyond 300 yards.
While the 7x57 fares well at 300-500 yards. The 6.5x55, 270, 30/06 all shot about like your rifle also and shot decent at 300-500 also.
All of these were shot only with handloads, the 30/06 really liked Sierra 165grain spire point boat tails.
Some of your loads are good enough I would have settled for them or played with seating depth.
That is a beautiful rifle and the bedding looks excellent, looks like a great all around hunting rifle.
I know mule deer have been killed at over 500 yards with the 6.5x55, 7x57 and 30/06 that I have had and yours should make a great hunting rifle

 

[greenejc]

Here is the ocw with varget powder. I plan on loading 44.4 and playing with seating depth and if nothing changes I ordered some 155 Berger hunting vld's to try. View attachment 325005View attachment 325004

Something I just remembered about light barrels which I had to do with my Ruger 30-06. A light barrel 'whips', which means it will actually move in a (very slight) circle at the muzzle in the opposite direction of the rifling as the bullet goes down the barrel. If the bullet exits the barrel at the top the barrel's arc, most of the lateral spread of the group will go away. 'Accuracy nodes' are where this is happening consistently in a light barrel. If you get a load like no. 7 or 8 above, where you're getting a nice triangular group, that's probably where you're at the top of the barrel's arc. If it shoots the classic hunter like that, that's about as good as you need or can expect. I'd work up or down from that by 0.2 grain increments to see when it starts to spread, and that will give you a range for your powder charge, then I'd try other 165 to 168 grain hunting bullets to see how they behave, but that's a really good load at no. 7 & 8, with a 24 fps spread between shots. Your flier on the 8th group is due to the difference in MV. No. 5 is also one to explore by going up or down in 0.2 grain increments. Burn rate is very consistent and it is at the top of the barrel vibration arc.

 

[WildRose]

Great information
But I'm a little bit confused
How did you use a brass screw and lapping compound to polish the crown
Was the screw actually used as a tool to hold the lapping compound
My son works at a race shop building race car engine and he uses a hand tool to hand polish valves in a cylinder head
So is that about the same kind a of tool

Midway and Brownell's carry a piloted crown cleanup tool for a few bucks which I've used with great success.

 

[WildRose]

I have owned a 1/2 dozen of the earlier 80's era Winchester featherweights, running from 257 Roberts through 30/06.
I still have the 257 and a 7x57. The only one that shoots considerably better than your rifle is the 257, it seems to throw about any load I try at 3/4" or less at 100 yards. The 7x57 shoots about with your rifle at 100 yards. I always shoot 3 shot groups.
Even though the 257 shoots lights out at 100 yards it opens up at longer distances to unacceptable groups beyond 300 yards.
While the 7x57 fares well at 300-500 yards. The 6.5x55, 270, 30/06 all shot about like your rifle also and shot decent at 300-500 also.
All of these were shot only with handloads, the 30/06 really liked Sierra 165grain spire point boat tails.
Some of your loads are good enough I would have settled for them or played with seating depth.
That is a beautiful rifle and the bedding looks excellent, looks like a great all around hunting rifle.
I know mule deer have been killed at over 500 yards with the 6.5x55, 7x57 and 30/06 that I have had and yours should make a great hunting rifle

WBY's have slow twist, particularly older WBY Barrels. The 120-130 class bullets should perform well if you can work up a good load for them.

 

[Huntz]

I have had good luck in Win.70 featherweights by full length bedding the barrel.I had talked to Melvin Forbes and that is what he recommended trying out.Truth fully your rifle is shooting respectable groups.If shooting long range was your goal maybe what you have is not the right combination.Good luck,Huntz

 

[SSG Graybush]

I have a newer fn Winchester model 70 I have pillar bedded put in a timney trigger and had a pacnor super match barrel fitted and chambered with a 308 bisley reamer in the factory featherweight contour. I'm getting 1-1.5 moa with 168 fgmm and have worked up a 1 moa load with 168 Berger classic hunters and 4064 powder. Was kind of disappointed in the accuracy and was wondering if this is on par for this skinny of a barrel.View attachment 324783View attachment 324784View attachment 324785View attachment 324786View attachment 324787View attachment 324788View attachment 324789View attachment 324790

My factory mod 70 FW 270 wsm shoots .5 moa ish with 130 gr Berger CH's, and Nosler BT's and AB's. I put in the Timney trigger and bedded it was well in a B&C stock. Try Varget as a powder, maybe.

 

[esshup]

I have a question for you. What is the distance from the ogive of the bullet to the lands/grooves?

Here is what I would do. (I have a #2 contour .243 barrel on a factory Browning A-Bolt Mountain Ti - the gun is 6 lb 2 oz with scope and full mag.) Shooting a 3 shot group is all I can do without the barrel getting too hot. So I know about pencil barrels. Too hot is when you cannot hold your hand on the barrel right in front of the scope for 30 seconds without yanking your hand away..... I thought I had the gun dialed in and shooting 1/2 moa was all that it could do. Then I re-read the bullet seating depth info on the bullets I was using and it said to start load development at .050" off the lands. (I was .017" off). I tried that and the group size shrunk another 1/8 moa. I played around more and got the gun to shoot 1/4 moa from 100 to 400 yds (I have a range here at the house).

Anyway.

I would take this load:
Lapua Case
Fed 210M Primer
44.3 IMR-4064
Berger 168g Classic Hunter
2.201 CBTO

I would take this load at that CBTO and check to see what the "jump" to the lands/grooves is at that seating depth (just for reference sake). I would load 3 that were 2.204" CBTO and 3 at 2.198" CBTO and see what the groups look like. If either of those shoot a tighter group, move the seating depth another .003" in that direction and shoot another group. Keep moving the seating depth .003" in that direction until the groups start to open up. Then stop and go back to the seating depth that had the tightest group. Seat the bullet further out in .001" increments until the group opens up. Once that happens, deduct .002" from the CBTO seating depth and call it good.

I don't like the 43.9g load because the 43.5g load is a worse group. If the temp drops and you are using the 43.5g load, then the group might open up. I always pick the middle powder charge of a node (which looks to be 44.3g in this instance) and then play with seating depth in .003" increments so I have leeway on both sides of the powder charge for temp changes.

I am using RL-15 for my factory FN SPR 26" barrel .308 (standard chamber) with 168 or 175 SMK's for punching steel out to 1K. It is my practice gun, I have a 7mm Allen Magnum that I use for long distance hunting and it is a lot cheaper to shoot the .308. (3 shots is all I can do with that 7mm AM before the barrel gets too hot to shoot.) It will shoot 3/8-1/2 moa out to 1K with the 168's, during the summer then they start to go subsonic. I can shoot at 1K with the 175's at 1K during the winter before they start to start to open up because of starting to go subsonic. That transition between supersonic and subsonic is what upsets the bullet.

I hope this helps.

Scott

 

[stovepipe]

Mark. I was having pretty much the same issues as you with my Remington mountain rifle (pencil barrel) 308 , like you I tried 4064 with so so results. I picked up some 178 eld m and switched to varget...problem solved. This is 3 shots @ 100

 

[Rflshootr]

I would try a different primer. It can make a considerable difference. Recently I was working up a load for my bench gun and decided to try some staball powder. I started with federal primers and was getting hang fires on the first 3 loads. Once I got up near max charge, the hang fire went away. So then I tried remington and winchester primers leaving my known bullet seating depth the same for all the tests. The rem primers shot an agg of .329 over 4 powder charges and a small group of .180. The winchester primers shot an agg .534 over the same 4 powder charges with the small group being .377. I have 2 308's and in my experience with 4064, the WLR primer performs best. I would give that a try if you have any or could get your hands on some. You see many targets on the net where it is just one target where a gun shot a good group. When it will do it consistently, you know you have it right. Btw, the outer circle on that target is .450 diameter in case you were wondering.
The other thing I notice is the depth of the crown. I personally have had better luck with shallower crowns... .015-.025 deep. It's hard to tell from the pic but, is the pattern on the crown equal at each land? It has also been my experience that Bergers like to be anywhere from touching to .010 into the lands. That's not far enough in to stick a bullet btw.