257 Roberts Ackley Improved

[Dr T]

I am thinking about picking up a 257 Roberts Ackley Improved (40 degree shoulder) barrel for my T/C Encore.

1. What sort of accuracy should be expected from factory ammo in 257 Roberts (when compared to loads in fireformed brass)? In general, how does factory ammo for a standard round behave in a rifle chambered for an improved round.

2. What sort of load should be used to fireform the brass (other than factory, which gets expensive), e.g. Will minimum listed 257 Roberts loads work?

2. I interpret the text in the Hornady manual for for the 257 R Improved (28 degree) that the listed loads should be safe in the 40 degree version (but due care should be exercised as maximum is approached). Is this correct?

 

[Clipper]

I'm shooting factory +P in my AI chambered custom Mauser...It's a 1-hole rifle. I haven't started loading for it yet.

 

[Dr T]

Thanks. Any extraction issues?

 

[Clipper]

None. The rifle functions flawlessly. So far I've only used Hornady and Winchester ammo.

 

[greyling22]

I've fired 257 bob through my 257 AI. I honestly couldn't tell much difference in recoil, extraction etc. Point of impact was only slightly off.

 

[35 Whelen]

1. What sort of accuracy should be expected from factory ammo in 257 Roberts (when compared to loads in fireformed brass)? In general, how does factory ammo for a standard round behave in a rifle chambered for an improved round.

Accuracy should be close to the same.

2. What sort of load should be used to fireform the brass (other than factory, which gets expensive), e.g. Will minimum listed 257 Roberts loads work?

Save your bullets and powder. There's a really cheap, easy and safe way to fire-form brass. I've used this method for my 257 AI as well as my fathers 338-06 AI.
Size and prime a case then charge it with about 5-6 grs. of pistol powder, something along the lines of Unique. I've used Red Dot, Green Dot Unique and Herco and they all work. Next, fill the case to within 1/8" to 1/4" of the mouth with Cream of Wheat or cornmeal. Now plug the mouth of the case with candlewax by pushing the mouth of the case into the side of a candle then breaking off the plug of wax by twisting the case. I use my wifes decorative candles. If you do this, just be sure to take the plugs from the backside if the candles so she won't know.
Now just take the loaded cases outside and fire them up in the air. Be aware that the Cream of Wheat or cornmeal can be VERY dangerous at close range, so always point the rifle in a safe direction.
since the aforementioned charge is so light and produces so little pressure, the shoulders probably won't fully form but that's no big deal. You can either add a grain of powder or better yet, I usually smear a little case sizing lube on the shoulder.
I've owned my 257 AI for over 20 years and have formed gobs of cases using this method.

2. I interpret the text in the Hornady manual for for the 257 R Improved (28 degree) that the listed loads should be safe in the 40 degree version (but due care should be exercised as maximum is approached). Is this correct?

All things equal, the loads for the 28° AI should be safe in the 40° AI because the latter has a slightly greater case capacity. But of course, use caution when working up loads.
I used a lot of WW760 in my AI and could occassionally get 3300 fps with a 100 gr. bullet. Killed lots of deer and hogs with various 100 gr. bullets but finally settled on the 100 gr. Remington Core-Lokt. Fine little bullet with good weight retention.
Good luck,
35W

 

[snake284]

Building a .257 AI

I'm having one built as we speek. I have a few Yugo Mausers I bought for doners. I'm having a 27 Inch Shillen barrel put on it. First, my gun smith will bend the bolt and drill and tap the action for scope mounts. Then he's going to put on a Timney Sporter Trigger and a three position Model 70 style trigger on it. And finally fit the barrel. I have the stock here that I ordered from Boyds, and I'll finish it hopefully before he gets through with the metalworkings. As for as glass goes, he already ordered and received a Leupold VX-3L 4.5-14X56 MM with side focus for parrallax adjudtment. This is one of the scopes that has the half round cut out to fit down over the barrel so that even with a 50-56 MM Objective lense, you could get by with lower rings. I'm curious to see how bright this scope is. It should be because it cost me more than any two other scopes have ever bought.

 

[35 Whelen]

Sounds like it
s going to be a nice rig, Snake. the scope will be bright for sure, but no brighter than a good ol' 3-9x40 Leupold. Those massive objectives only help with brightness to a certain point.
35W

 

[Dr T]

Thanks for the fire-forming methodology. I have heard about it, but never seen a good explanation. The only problem is going outside the garage to fire them off. If I was down on the ranch in West Texas, I wouldn't have a problem, but right now it might be frowned upon in the Denver area.

I am still thinking about this project. For glass I would be leaning towards a Burris 2-7x with the German 3P crosshairs. I have one on the 30-06 Encore barrel and it has worked out well.

 

[Clark]

I built (4) 257 Roberts Ackley Improved rifles in 2002 with Lothar Walther light varmint taper barrels from Brownells.

One was for me.
I put it on a VZ24 action.

With 72 and 75 gr bullets it averages .75" 5 shots at 100 yards, with the best group at .45"
With 100 gr bullets it averages 1" 5 shots at 100 yards.

With 115 and 117 gr bullets it averages 1.2" 5 shots at 100 yards.

My rifle was the first, and I made the mistake of using a piece o 257 brass as the go gauge.
The headspace should be .004" tighter, so the firing pin cannot push the case forward by crushing the edge of the chamber neck base into the case.

As a result I have had to fire form with cream of wheat.

The way I see it, the who Ackley Improved thing is an extra step to fire form without offsetting benefits.

 

[da2mag]

I have a .257 improved in a bolt gun and when I have used regular loads fireforming brass and have even tried .257 improved loads in unformed brass to fireform it with good results. I still get good accuracy but I am sure the velocity is down a bit. I have used this ammo to hunt coyotes with while fireforming brass and the coyotes really have not seemed to notice the lack of a few feet per second. As with most guns accuracy does improve after the brass is fireformed to the chamber of the gun and after I have them fireformed I usually just neck size. Hmm...... .257 imp. in an Encore with a 28" tube......now you have me thinking. That would be one fun little unit and I have a couple of encore frames laying around.