Sako A1 22PPC project

[AlNyhus]

Here's my Sako A1 single shot in 22PPC, circa 1988. I'd been wanting one for a long time and finally found one this Winter in like-new condition. Kind of a back-to-my-roots gun!

The bedding was pretty wonky and needed to be corrected before doing any range work. Loosening/tightening the front action screw showed over .020 of movement. The front action screw threads into the bottom of the recoil lug on these (yuk) and it was making little, if any contact. I bedded the bottom of the lug but it didn't help. At that point, a high spot in the bedding was the likely suspect.

As Jackie Gleason would say...away we go.

On the mill, I opened the action screw holes to 5/16" and then used a 5/8" counterbore with a 5/16" pilot to enlarge the action screw holes for pillars.

Next, with the stock perfectly leveled in the mill, I removed the old bedding. This confirmed my suspicions as you can clearly see the area that the cutter isn't touching....the bedding was high in the back.

Here's the corrected action bedding area now...flat and straight. I also milled out the recoil lug mortise and milled two channels to hold some bedding epoxy. Flat bottomed actions like the Sako can easily get a high spot in the bedding. On a round bottom action, bedding will want to push out and up so it's less of an issue. With the flat bottoms, you need to provide more room for the excess to go. You can see where there were holes drilled originally for the bedding to flow into.

Made up the pillars from some 6061 round stock:

The center one needs a notch for the trigger mounting. Rather than cut into the hole for the action screw area like you have to do with a Savage, I split the difference and machined .040 off the front of the trigger mounting boss.

A view from the top.

Front pillar with recess for button head action screw.

These sleeves are 5/16" o.d. and fit into the recess I machined into the front pillar. The i.d. is a snug fit to the long pilot screws that thread into the action...so when it's done, the action screws are perfectly centered in the pillars with plenty of clearance around them:

Mix a little Pro Bed....

....and we're in.

More pics to come. -Al

 

[AlNyhus]

Lightly clamped and waiting 24 hrs.

Out of the bedding and on to final clean up. The screw holes are deburred and chamfered, the edges are rolled over....generally make sure there are no edges or high spots to prevent the action from lying perfectly on the bedding. An assortment of small files, scalpels, well used strips of sandpaper and some cone shaped stones are good for this.

Bedding clean up done and it's time to check the work. My approach to pillar bedding is that when the action screws are removed, the barrelled action should literally fall out of the stock...no tugging, no tightness. If there is, there's something preventing the action from making perfect contact with the bedding compound and it's inducing stress in the bedded barrelled action. As you check the bedding, stand the rifle up on the butt with the action screws slightly loose and thump the butt on the floor to seat the recoil lug. Now, snug the screws evenly. With the barrel still pointing up and the butt on the floor, put your finger on the barrel at the end of the stock fore end and crack the front action screw loose. You should feel little, if any movement. Then tighten the front screw do the other action screws and see what happens. If this all feels good and the barrelled action is loose in the stock, you're there.

You can attach a magnetic base with a dial indicator like this if you wish to double check:

Cracking the front screw loose, this Sako moves just a fuzz over .001. I probably could have got it down a bit further by orienting the indicator plunger exactly 90...but you get the idea.

At this point, I consider the bedding done. Will reinstall the bolt release and go on to the next part of the project.

Good shootin'.

 

[AlNyhus]

Lapped and bedded the scope rings:

Leupold rings installed:

Closer view of the ridges that Leupold puts in their rings. They actually do a pretty good job:

What I use for a compound. Ring bottoms have the compound applied:

My home made lapping bar is a 1" bar, drilled/tapped 3/8X16 with a bolt as a handle:

This is after a dozen strokes with fairly heavy pressure. I continued until the ridges were gone, then cleaned the rings with acetone:

I used Pro Bed on these. Brownell's AcraGlas Gel really works well as it has Nylon in it....you want some flexibility. I used some medical grade Nylon powder and mixed that in with the Pro Bed:

A light oil like this shotgun choke tube oil goes on the screws, ring tops and the outside of the rings. On the lapping bar, use the regular mold release agent that you normally use for bedding:

Then lightly snug the caps down. The lapping bar handle goes to the side so it doesn't rotate:

Curing:

 

[AlNyhus]

Here's the result of the ring lapping and bedding. If you compare this to the 'before' pic...even assuming that the 'ridges' were making 100% in contact...the 'after' pic clearly shows a doubling of the contact area. It's hard to see in these pics but a small file works to relieve the parting lines at the top. If you look back at the pic of the Kelbly rings, it's better of that area :

On the ring tops, I lap them on the bar and repeat the process:

Lapped the top ring halves. They were pretty round out of the box.

Since there wasn't much taken off, the Pro Bed was thinned a bit. Chamfered the edges and the gun is ready for a scope and some range time.

Good shootin'. -Al

 

[AlNyhus]

Randy Robinett at BIB was kind enough to make up some .673 long .22's to test out of my Sako A1 22PPC. With a measured 14 barrel twist, the math on the default BR 52 gr. bullet doesn't hold up for stability. Randy's 52's are killer good in a 13 twist, by the way.

Powders tried were H322, Benchmark, N133, H4198 and the 'new' WW748.

Yes, it's a sample of one. Certainly not a real-deal BR rig by any stretch of the imagination and it's got a factory barrel and chamber to boot. It does make me wonder how many 'tuning' issues with the PPC's are really bullet length/twist rate issues. If they can shoot this well in an tuned up factory gun...sheesh.

Good shootin'. -Al

 

[th82457]

Excellant write-up & very nice rifle. I have a Cooper in .22 PPC. I think you are correct of bullet length/stability with 14 twist. Mine shoots 40 grain V-Max & Sierras into very consistent small groups. Does not like longer 52-55 grain bullets nearly as much. Congrats on a fine Sako.

 

[Mark M.]

Excellent post

 

[Gary in MD]

Excellent job and write up.
Thanks for posting,
Gary

 

[JSH]

Al, that is a nice rig along with some nice work.
The taper in the aluminum pillars, I have mixed thoughts on those or a flat bottom. The taper with a nice finish I doubt will cause any issues over time, I am thinking of galding. A flat bottom with a washer is what I like.

I have both types, I have found torque of action screws has some definite impact on things. The “feel” on some tapers just doesn’t feel proper to me at times.

 

[AlNyhus]

Al, that is a nice rig along with some nice work.
The taper in the aluminum pillars, I have mixed thoughts on those or a flat bottom. The taper with a nice finish I doubt will cause any issues over time, I am thinking of galding. A flat bottom with a washer is what I like.

I have both types, I have found torque of action screws has some definite impact on things. The “feel” on some tapers just doesn’t feel proper to me at times.

Here's a couple of pics on the bottom metal. The middle and rear pillars are flat to mate with the factory bottom metal.

The front pillar does not use a tapered seat action screw. Rather, it's a flat head button screw. The flat head gives more contact surface and eliminates the screws torquing the action as they are snugged down. Done correctly, a 'flat-to-flat' pillar and action screw set up won't show any differences in how tight the screws are tightened. They should come up to 'tight' instantly.

These do.

 

[AlNyhus]

To answer the front pillar question, here's a couple pics of how I make the recessed pillars. These pics were of another project but the Sako front pillar was done the same way with the exception of the O.D.

 

[LCazador]

Beautiful job and great pics on the post and a great post overall. This was one for the pages of the old magazine The Accurate Rifle or Precision Shooting magazine. Craftsmen like you are few these days!

 

[Ramblerman]

Beautiful job and great pics on the post and a great post overall. This was one for the pages of the old magazine The Accurate Rifle or Precision Shooting magazine. Craftsmen like you are few these days!

Totally agree, love seeing this type of stuff here! Great to share the different ideas and processes we all have.

 

[Racebannon3855]

Thank You for taking the time to post this. I am trying to get organized enough to finish my shop this summer. Your work on this has inspired me to get it done. No more mill and lathe in storage, need to get them set up and under power.

 

[17VLD]

Very nice thread Al,really enjoyed reading and your pics.
That rifle would surely win all our local HBR matches.
I bet those BIBs would work in my 22ppc Cooper very nicely.
Matt

 

[AlNyhus]

Very nice thread Al,really enjoyed reading and your pics. That rifle would surely win all our local HBR matches.I bet those BIBs would work in my 22ppc Cooper very nicely. Matt

Hi Matt...good to hear from you and hope you're doing well. -Al

 

[Capt. Oblivious]

Very nice, thanks for sharing

 

[GoWyo!]

Hi Al,

I read this over on SCC. Outstanding work. I bought the same rifle a couple years back and have yet to get it to the range. I have no machining experience, no BR experience, so my OEM expectations/ results will be taken with a grain of salt. I haven't even pulled the action to see if it's been bedded. Your post has given me the inspiration to get out and shoot it this spring/ early summer.

Gary