Shilen bbl for CZ457 American

[flatlander]

I finally got the Shilen select match ratchet rifled #5 blank finished for the CZ457 American I wrote about back in February. This is the first CZ .22RF I've ever owned or shot, and as impressed with its features & attractive stock as I was, accuracy wasn't acceptable. After removing the OEM bbl and cutting a new 11* crown, accuracy improved a bit, but was still not good or consistent enough to suit, averaging 2 MOA or more at 50yds most of the time.

I'd looked around for an easy solution, but was put off by some negative posts about various brands of bbls. Finally decided to go with a Shilen blank, and chose Shilen's #5 blank. Didn't want to turn down the 1.25" dia shank, so parted it off at the front edge where it transitions to the radius. I turned the radius down to .925", which left a straight shank of about 3" in length, and which also transitioned nicely into the straight tapered portion of the blank. After parting off an inch at the muzzle, I wound up with a finished length of 23", which weighed just over 1/2lb more than the OEM 24" American bbl.

Though I'd considered threading the 457 action, I decided against it for a couple of different reasons - not the least of which was the possibility of screwing up and winding up with an expensive paper weight. Instead, I by-passed making the cuts for the grub screws to bear against, and used Loctite 609 retaining fluid to glue the bbl into the 457's bbl socket. After joining the action & bbl, I used some leather strips to protect the action from the jaws of the 4-jaw chuck on my lathe, and pushed the tailstock up against the thread protector on the Shilen's muzzle, then cranked a bit of pressure on the muzzle with the tailstock. Left it in the lathe overnight, and removed it after a little over 12hrs.

Before gluing the bbl into the action, I'd de-greased, blasted, and CeraKoted the bbl, thread protector, and a new bolt knob I'd turned on the lathe for my 457 MTR. I mixed 20ml graphite black & 10ml tungsten in an attempt to match the nitride finish of the 457 - the bbl is still a bit darker than the action, but it's close, and looks pretty good IMHO. At least the thread protector matches the bbl...

I took the rifle out yesterday morning while the breeze was still pretty light and shot it off Doggone Good Bag front & rear bags on steel at 50yds to get a rough zero, then switched to paper targets. Shot initially with a good lot of SK Std+ and managed to put four rounds into what I thought was shaping up into a decent group before seeing some weird recoil/tracking on the fifth shot - see attached photo. Was running out of time, but did more hurried shooting with SK Pistol Match, LR match, Flatnose Basic, and Lapua Center-X. Both Flatnose Basic & LR Match put six or seven out of ten shots basically into the same hole, with the other three or four shots not more than 1/4' away. Rewarding and confidence inspiring, especially since my position wasn't comfortable and I was in a hurry. Next time out, I'll take time to set up the bench and get into a more comfortable position. This is the first Shilen bbl I've ever worked with - based on what I saw yesterday, it probably won't be the last.

This is so much better than what I was seeing with the OEM bbl, but I'm still hoping for some improvement next time out - when I got the rifle back into the shop, I thought about checking the bbl channel to see if it was still free floating, and found some contact out at the last 4" or so of the forend. I'd stopped sanding on the bbl channel after getting the bbl floated, but hadn't checked with the action screws torqued tight (25in/lbs rear, 20in/lbs front). It won't take much more sanding to clear out the contact I found yesterday, then I can put a coat or two of urethane varnish in the sanded portion of the bbl channel to seal it again. I've got to pull the bbl'd action anyway to engrave the chambering on the bbl, so while we're getting dumped on with rain again, might as well get the finishing touches done.

[squirrel1]

My Lilja barrel on 455 after cleaning will shoot sk and wolf real good at 50 yards. One problem though. Only for around 30 shots then groups at 50 yards are around 3/4” ctc.

Barrel don’t like this ammo. Plain and simple. One could be lured into a false sense of security though if they just shot 20 or so rounds of it.

It does the same thing using this ammo coming off of cci standard too, and other brands of rounds instead of cleaning.

[bearhunter 500]

Nice write up Flatlander. How about pic of the rifle it self? What chamber reamer did you use?

[homersapien]

Did you slug the barrel to identify the best location for the crown? I dont have the equipment to do my own barrel so I'm stuck with OEM, but I did finally glue in a CZ factory barrel and it made the most improvement to my rifle. I dont think you are missing much by not threading.

[flatlander]

Not a great photo, as it doesn't show how nice the grain in the buttstock is, but I did put the OEM American bbl there for comparison. It's just a little muzzle heavy now, while before, it was nearly perfectly balanced.

I used a PTG EPS reamer, same reamer I've used on my other customs for Stiller, 40X & XB repeaters, and the first V-22 that I bought as an action and then barreled myself. This reamer gives good results with Eley Match in the other rifles, as you'd expect from a reamer named after Eley's EPS bullet. But I don't think it gives up any accuracy with SK/Lapua ammo.

Nope, did not slug the bore - Shilen advertises these blanks as being taper lapped, so it shouldn't make any difference where you put the muzzle. When I get decent conditions for shooting again, I'll try to get some photos of 10-shot groups at 100 & 210yds posted. It rained fairly hard last night, and is still showering on & off through the day so far. Radar shows a good bit more heavy rain headed our way - hope it comes w/o high winds & hail....