CZ 457 PRS Build

[EugeneM]

Lots of shooting, but you are right, nothing that would stand out.
Any chance you have a picture of your shooting setup? are you using a bipod? how do you support your rifle at the back? with this level of accuracy, every detail matters.
PS. two later pictures of the groups are not showing, but when you click on the image icon, it would open the proper picture

 

[Leuchtkafer]

Lots of shooting, but you are right, nothing that would stand out.
Any chance you have a picture of your shooting setup? are you using a bipod? how do you support your rifle at the back? with this level of accuracy, every detail matters.
PS. two later pictures of the groups are not showing, but when you click on the image icon, it would open the proper picture

I've got a pic of the setup with the factory rifle, only change is the front bag to a medium width for the PRS chassis. The chassis isn't the greatest fit on the rear bag, I compensate for that with a firm hold.

 

[EugeneM]

I've got a pic of the setup with the factory rifle, only change is the front bag to a medium width for the PRS chassis. The chassis isn't the greatest fit on the rear bag, I compensate for that with a firm hold.

I see. From my experience, this setup is not the best one for consistency. There seems to be a whole science as to how the seasoned benchresters make such setup work, it's all about the details, rifle bein able to slide in the rest, and it's a subject big enough for a separate thread on this forum.
If you do the same ammo testing with a bipod, while properly loading it, I am sure you will see a significant improvement in your groups.

 

[dastt]

literally all your groups are suitable for PRS shooting. i think youre overthinking ammo performance needs.

if youre just starting out, it will be a long time before you start out shooting your ammo from a barricade.

also, a short barrel isnt optimal for a prs set up when balance is the number 1 important thing.

in my experience there is no "break in" in a 22, and most custom barrels will run really good right out of the get go. the only thing that requires any sort of attention in a rimfire barrel is the carbon ring, you never need to clean out the full barrel.

 

[Leuchtkafer]

I see. From my experience, this setup is not the best one for consistency. There seems to be a whole science as to how the seasoned benchresters make such setup work, it's all about the details, rifle bein able to slide in the rest, and it's a subject big enough for a separate thread on this forum.
If you do the same ammo testing with a bipod, while properly loading it, I am sure you will see a significant improvement in your groups.

What can I say, I've shot with this setup for many years. I've learned how to overcome it's shortcomings and achieve a certain level of results with a number of different rifles. I can accept that here and there, I'll turn a group in the 0.2's into a high 0.3's-0.4x with a lapse in concentration, that's realistically plausible. If you study the groups again, with how frequently the fliers occur, does it make sense that I'm turning a 0.2 or better group into a 0.6+ because of the setup? In my view from my experience, that points to something else that I can't really control, be it the ammo or the barrel.

literally all your groups are suitable for PRS shooting. i think youre overthinking ammo performance needs.

if youre just starting out, it will be a long time before you start out shooting your ammo from a barricade.

also, a short barrel isnt optimal for a prs set up when balance is the number 1 important thing.

in my experience there is no "break in" in a 22, and most custom barrels will run really good right out of the get go. the only thing that requires any sort of attention in a rimfire barrel is the carbon ring, you never need to clean out the full barrel.

I appreciate the feedback, I'm just feeling a little let down knowing what performance builds like this can be capable of. I'm trying to balance that out against the fact that it's still fit for it's intended use. I know the short barrel wasn't ideal, I was just working with what I've got. This wasn't a new blank that I used so I couldn't make it any longer. Actually I had to shorten it by an inch and a quarter from what it was on the other rifle. I wanted to see if I could give this barrel a second chance at life, it had the same symptoms on the other rifle. About all I could see wrong with it was a little gouge in the chamber right where the carbon ring grew that would lead up. I thought maybe a new chamber to eliminate that might cure it, doesn't seem to have worked out though. The only other thing I can see is that one land/groove section of the barrel has a rough gnarly pitted texture to it, and it's like that the entire way down the bore. I don't know if that's the reason, it's just something I can see.



I spin the borescope around and the other sections of the bore are nice and smooth like you'd expect in a custom barrel.



Keep in mind, my projects often serve multiple purposes. I'm not just building a PRS rifle, I'm also trying to learn the ins and outs of high level rimfire accuracy. My other option was to just toss this barrel in the scrap bin and start with a fresh blank, but that'd waste a learning opportunity. There's not much left I can do to this barrel to try to improve it. Noting the rough texture, doing some lapping is the only play left so that's what I did tonight. I either just ruined it, made it better, or had little to no effect. If it still shoots the same or a little better, I'll leave it at that and get some service out of it for PRS. You're right about shooting off a barricade, no way I can shoot at the same level as the rifle. Yeah I'm collecting a strong body of evidence that a barrel either "has it" or it doesn't, and there are very limited circumstances where an obvious flaw can be identified and remedied.

 

[dastt]

What can I say, I've shot with this setup for many years. I've learned how to overcome it's shortcomings and achieve a certain level of results with a number of different rifles. I can accept that here and there, I'll turn a group in the 0.2's into a high 0.3's-0.4x with a lapse in concentration, that's realistically plausible. If you study the groups again, with how frequently the fliers occur, does it make sense that I'm turning a 0.2 or better group into a 0.6+ because of the setup? In my view from my experience, that points to something else that I can't really control, be it the ammo or the barrel.


I appreciate the feedback, I'm just feeling a little let down knowing what performance builds like this can be capable of. I'm trying to balance that out against the fact that it's still fit for it's intended use. I know the short barrel wasn't ideal, I was just working with what I've got. This wasn't a new blank that I used so I couldn't make it any longer. Actually I had to shorten it by an inch and a quarter from what it was on the other rifle. I wanted to see if I could give this barrel a second chance at life, it had the same symptoms on the other rifle. About all I could see wrong with it was a little gouge in the chamber right where the carbon ring grew that would lead up. I thought maybe a new chamber to eliminate that might cure it, doesn't seem to have worked out though. The only other thing I can see is that one land/groove section of the barrel has a rough gnarly pitted texture to it, and it's like that the entire way down the bore. I don't know if that's the reason, it's just something I can see.



I spin the borescope around and the other sections of the bore are nice and smooth like you'd expect in a custom barrel.



Keep in mind, my projects often serve multiple purposes. I'm not just building a PRS rifle, I'm also trying to learn the ins and outs of high level rimfire accuracy. My other option was to just toss this barrel in the scrap bin and start with a fresh blank, but that'd waste a learning opportunity. There's not much left I can do to this barrel to try to improve it. Noting the rough texture, doing some lapping is the only play left so that's what I did tonight. I either just ruined it, made it better, or had little to no effect. If it still shoots the same or a little better, I'll leave it at that and get some service out of it for PRS. You're right about shooting off a barricade, no way I can shoot at the same level as the rifle. Yeah I'm collecting a strong body of evidence that a barrel either "has it" or it doesn't, and there are very limited circumstances where an obvious flaw can be identified and remedied.

From what I’ve seen, rimfire barrels are far less picky on small imperfections in the barrel like a CF, keep in mind the projectile is soft lead. When barrels get “seasoned” and it increases velocity and you gain some accuracy, that’s just the lead from bullets filling in any imperfections along the length of the barrel. That’s why it’s not always great to clean the entire barrel. Just the carbon ring, which will actually squeeze the lead as it goes through.

I’ve shot 80+ .22 prs matches, and I can say those groups you’ve posted are smaller than 95% of the groups I see on the zero board in the morning.

I wouldn’t get too hung up on it, just get out and shoot! That rig is more then capable of going as far as you want to take the sport.

 

[Leuchtkafer]

From what I’ve seen, rimfire barrels are far less picky on small imperfections in the barrel like a CF, keep in mind the projectile is soft lead. When barrels get “seasoned” and it increases velocity and you gain some accuracy, that’s just the lead from bullets filling in any imperfections along the length of the barrel. That’s why it’s not always great to clean the entire barrel. Just the carbon ring, which will actually squeeze the lead as it goes through.

I’ve shot 80+ .22 prs matches, and I can say those groups you’ve posted are smaller than 95% of the groups I see on the zero board in the morning.

I wouldn’t get too hung up on it, just get out and shoot! That rig is more then capable of going as far as you want to take the sport.

Yeah one of my first rifles looked like train tracks down the bore from machining, still shot pretty good. Speaking of the carbon ring, I saved the chamber nub from this barrel that I cut off before fitting to this build, and took a pic of that gouge I mentioned. I noticed carbon/lead would build up on this spot more than the rest of the chamber, and wondered if that was why I was getting those odd fliers. That was my reasoning for using it for this build, worst case it'd shoot the same and that'd be fine for PRS, but maybe cutting a fresh clean chamber stood a chance of fixing the issue. Now that I look at it again, it doesn't appear to be any kind of machining mark, the edges are too irregular. Now I'm wondering if there's some metallurgical issue with the steel, bad batch with impurities or something, causing it to "rot out", so to speak. I'll have to keep an eye out if something similar happens to the new chamber, which is pristine right now.



Just behind that gouge is another one, though it's behind the carbon ring area and the casing sits over it so it wouldn't have affected the bullet in any way. Again doesn't appear to have come from machining.



Hehe, it's not easy for me to change gears and step back from the madness of pursuing bug-hole groups, though that's why I wanted to get into PRS. I do have some excellent shooting rifles, but the way things are with getting good ammo these days to feed them properly has only become more of an exercise in frustration as time goes on. Better to change disciplines to something that takes the focus off the gear and puts it back on the shooter. Once I'm all set up and ringing steel the worries will melt away

 

[Leuchtkafer]

I was itching to get out to the range since I finished another project, the weather yesterday was as good as it's going to get for the foreseeable future and the mercury plunges again. A high of -3 and calm winds. I also wanted to shoot this build again since I had done some lapping after seeing the results of the first range day. I've picked out my rail and rings, put together an order including some fore end weights for balancing and a few bricks of SK and Lapua ammo. I tested most of the new ammo.



I would say the lapping helped a little bit, certainly didn't hurt. I'm much more satisfied with these results. The very last group with Lapua Long Range went a little squirrelly, hard to say why. At this point the cold had really set in on me, so it's very possible I just couldn't hold it together for one last group. Could also be the ammo, I've only shot one box of it so far so I haven't gotten to know the quality of the lot yet. As well, at 100 rounds fired the rifle could be telling me it's time for cleaning. Hard to say, so I'm not going to let that little blemish on the target spoil my day. The old lot of Center-X has fliers that push groups into the 0.5's in other rifles, that's not surprising to me to see here. I got two runs that would pass the 1/2" challenge, that's always satisfying.

I'm going to step back from accuracy testing for the rest of winter, aside from not being the most pleasant experience, the cold also brings out issues with the ammo. I was getting quite a few fail to fires, not so much here with the SK and Lapua, though there were a few, but with the other rifle and especially with RWS. Digging rounds out of the chamber to spin them around and try again is not my idea of a fun time at the range. That aside, I'm pleased with the progress on this build, it's turning into a fine little PRS rifle. Once I get the rail and scope mounted, the balancing weights installed, and make myself a custom bolt knob I'll take some pictures to show the completed build.

 

[Leuchtkafer]

Making A Custom Bolt Knob

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I took advantage of whatever days the temperatures weren't brutally freezing to work on this project over a couple weeks. No dimensions were really critical so this was something I could have some fun with. This is the kind of design that a CNC machine would be better suited to the task, doing it on a manual machine is very time consuming. It was about a 15 hour job. Started with a couple passes to set the major diameter.



I calculated out the cuts with a parting blade to rough in the profile



I did and "etch-a-sketch" method to remove the excess material left and refine the profile, then finished it with hand filing



Did some knurling



I made the spring loaded tap follower which helps greatly to hold the tap in alignment and make nice threads



Parted it off the finished the profile on the back end. Same concept roughing the profile with parting blade cuts, then finishing with a file until the coloured lines disappear and the sections blend together.



I gave it a high polish finish, here it is before bluing



Here it is blued up. I got some nice patina in the bluing.

 

[Leuchtkafer]

I went with an MDT 20 MOA rail, MDT Premier medium scope rings, and installed the interior fore end weights to balance. The weights are nicely made, good machining from MDT. The balance is almost perfect, a couple strips of lead tape should do the trick, though that'll change when I figure out a muzzle device and I'll need to re-evaluate.



The screws are countersunk, always a nice touch, and they come pre-loaded with a thread locking compound.





I haven't gotten around to taking proper pics of the finished build yet. Today was a nice day to hit the range, very welcome after that winter. I ran out of time to shoot this build much as I got carried away tuner testing my Anschutz. A note about tuners, you can't expect to slap on some random tuner that weighs whatever on a random barrel profile and have it work properly. You're lucky if that happens. Without a good way to pre-determine what a certain barrel needs, you have to test test test. If the barrel needs more weight, the Harrell tuner is good because weights are readily added to it. If it needs less weight, you're in a bit of a situation. This build I feel will need something lighter than a standard Harrell, I'll need to come up with something in the 5oz range I suspect.



I shot some Eley at 50 yards after sighting in the scope, results were just OK with it, Team and Tenex. I was left with only enough time to shoot these three groups at 100 yards. SK Semi-Auto was terrible, and I have a case of this stuff... I didn't need to shoot more than one group, it tells me all I need to know right there. That's not velocity variation, that's what happens when your barrel doesn't "like" the ammo. Keep that group in mind for if/when I get a tuner working on this rifle, it'll be easy to demonstrate a massive improvement with that ammo. It does showcase how much even a short rigid barrel moves, and why tuners are such an invaluable device when you can't find ammo that suits your naked barrel.

Lapua Long Range gave a nice sub 1" group, quality of the cartridges is there and it suits the barrel. I've only fired 75 rounds of it so consistency of the lot is still unknown, how many "surprises" in the boxes remains to be seen. SK HV Match was pretty decent too, I have a case of this as well. I'll go with using the SK HV Match for PRS, it should serve me well for a long time. Now I need to find a match to attend and get my feet wet in the sport

 

[Mysticprecision]

consider a much heavier tuner... like 14 to 16oz. You should move the balance point to at least the first MLOK slot if not further. you want it to be balanced ON a gamechanger which is 3 to 4" further forward vs where you are now.

You accuracy is plenty good but start testing at a min of 100yds if the prs matches go to 300+yds. If you have calm weather, with temps OVER 10C, 150yds is not too far.

Alot of ammo lot 'defects' will show up as you go to 100yds and beyond. If you can average 1" at 100yds over a number of groups, you are as good or better then the vast majority of rifles competing.

When you decide on your lot of Lapua whatever, know the percentage of flyers and where they generally go.... this will be important when shooting steel and not chasing a ghost.

Good luck and enjoy... PRS is not an accuracy game... it is a time management game.
.

Jerry

PS consider using the SK for practise and the Lapua for the match. If you can avoid ammo that WILL give you flyers in a match, that will make the experience so much more successful. Chasing ghosts gets real old, real fast...

 

[gorby]

consider a much heavier tuner... like 14 to 16oz. You should move the balance point to at least the first MLOK slot if not further. you want it to be balanced ON a gamechanger which is 3 to 4" further forward vs where you are now.

Yup, that is about where mine needs to be balanced on an MDT peanut bag. In practice, I have found the balance point needs to be further in front of the barricade stop than I first thought it would in order to rest unsupported on a shooting bag placed inline with the rifle over a ladder rung/barracade. I use a heavy tuner for the balance it provides, more than for its ability to tune.

Great thread and thanks to the OP for sharing the details!

 

[Leuchtkafer]

Thanks Jerry and gorby, good things to consider about the balance point. If the heavy tuner is just for balance, that won't be necessary on my build. A 5oz tuner will move the balance plenty, plus I have another 2 fore end weights I can still install if needed. I've found in the past that too heavy of a tuner does bad things to the barrel harmonics, like taking a good shooting ammo and making it perform like the SK Semi Auto. Better for the tuner to be too light for the barrel than too heavy, IMHO and experience.

I found an ORPS event to attend this Saturday, 25-100yd course of fire. We'll see how hard the competitive bug bites me before I go crazy with the ammo, I have plenty of the SK HV to use and I'm sure it'll be fine for me starting out at these distances. One other thing with my extra long custom bolt knob is that A: it is really easy to put too much off axis force on it and bind it up while cycling, and B: the length blocks my hand from falling back cleanly to the trigger, I have to do extra movement to go around it. I'll see how it plays, then I might end up cutting it back to just the diamond shape if it's too problematic. Shoot... I need to get myself some bags quick, Amazon Prime to the rescue!

 

[Jahnj0584]

Why buy a bag? There'll be 20 there you can borrow as you shoot the stage.

Ammo choice really isn't that critical. Smallest target is going to be what, 3"?

 

[gorby]

Thanks Jerry and gorby, good things to consider about the balance point. If the heavy tuner is just for balance, that won't be necessary on my build. A 5oz tuner will move the balance plenty, plus I have another 2 fore end weights I can still install if needed. I've found in the past that too heavy of a tuner does bad things to the barrel harmonics, like taking a good shooting ammo and making it perform like the SK Semi Auto. Better for the tuner to be too light for the barrel than too heavy, IMHO and experience.

I found an ORPS event to attend this Saturday, 25-100yd course of fire. We'll see how hard the competitive bug bites me before I go crazy with the ammo, I have plenty of the SK HV to use and I'm sure it'll be fine for me starting out at these distances. One other thing with my extra long custom bolt knob is that A: it is really easy to put too much off axis force on it and bind it up while cycling, and B: the length blocks my hand from falling back cleanly to the trigger, I have to do extra movement to go around it. I'll see how it plays, then I might end up cutting it back to just the diamond shape if it's too problematic. Shoot... I need to get myself some bags quick, Amazon Prime to the rescue!

Hesitant to give advice as you obviously have waaay more experience than I do, haha.

Totally agree with you that ORPs up to 100 does not require the best ammo. I found CCI Standard and Norma Tac are just fine at that distance for my stock cz barrel and I save my SK LRM for matches that go further.

As for the bags, the nice thing about the rimfire scene is how friendly everyone is, you will be able to try all the fancy shooting bags at your first match, so fine to show up with something basic. I used a random stuff sack with sand and borrowed specialty bags for a long time before getting something better.

Have fun!!!

 

[Leuchtkafer]

Right on, I do have a cheap bag that I used for bench shooting before I upgraded to a front rest, good to know that bags can be borrowed at events. I'm open to any advice on setting up the rifle and gear and accessories to get. My scope doesn't focus down to 25 yards, I forgot about that... I do have a Sightron SII 6-24x that does focus down to that range, though maybe my scope will be OK with the magnification zoomed out. We'll see, I'm looking forward to event day!

 

[Mysticprecision]

Put on the 6-24 and leave it at 12X. That should double the subtension value of the reticle (assume you have the LRMOA?). You do not need high mag for PRS. Make it more parallax friendly. The widest field of view and enough mag to clearly see the gong is plenty. Best to be able to see the air, where other targets are and maybe, any wind indicator. Also, when you miss, the lower mag lets you pick up where the impact went... on a windy day, that might be a foot or more away.

Remember that any 'out' caused by the ammo will be amplified due to the quirks of this game.... so that can create doubt on the 'why'

1 box of Lapua for the match will help you more then saving a few dollars and possibly missing more then necessary.

YMMV

Jerry

 

[EugeneM]

quick note on the scope. first focal plane and "christmas tree" reticle helps a lot! some stages can be "no dial", where you can only do holdovers which you won't be able to do with a crosshair.

 

[Leuchtkafer]

The SIII is the LRMOA reticle and the SII is a mil-dot reticle, both second focal plane.

 

[Leuchtkafer]

Match day was a blast, I had a ton of fun. I don't know what my score was yet, but I can tell you that I didn't win My custom bolt knob wasn't an issue like I was concerned it might be, it ran just fine. Build wise, zero issues chambering, extracting and ejecting, flawless performance. Goes to show concerns about tight chambers in repeaters may be slightly overblown, or speaks to my smithin' skills, you decide. I'm certainly feeling a certain satisfaction that not many can relate to. I didn't just bolt some components together and call it a rifle, I made steel chips fly and crafted this rifle to the fullest extent myself.

I added all 4 fore end weights and found that still didn't move the balance point far enough forward, weights close to the receiver have little effect on the balance. I did a quick and dirty external weight with a chunk of steel I had lying around, that made the balance good enough. Add it to my ever expanding machining project list to make the weight pretty at some point, but it's not a priority job. I might cut it in half so the two external weights can be mounted on either side of the stock right at the end of the fore stock for maximum balance effect, that'd be done when I get to making it pretty. Works for now so other jobs take precedence.

It was a very, very windy day so I'm glad we only shot to 100 yards, and it would have been a waste for me to use the Lapua Long Range. Jerry is coaching me like I'm a contender for first place when I'm just starting out, hehe. I have some learning and practice to do before the ammo starts holding me back. Maybe one day, but for now I'm happy shooting the SK HV. After the match I went to my range which was nearby for some more practice and took the pics I promised of the the finished build in it's element.