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Group size question==need advoce

Posted: Fri Jun 12, 2009 3:13 pm
by Doc One Shot
Hi
I just got my CZ HS precision stock in .204 back from CZ due to what I thought were bad groups. What size of groups should I expect ? How good is good ? I can get one ragged hole groups with me Savage .223, and thought I could get at least similar with this. I got a factory target back with a average of 1.09 from them.

I'm going to try different combinations, but what is this gun capable of ?
Thanks

Re: Group size question==need advoce

Posted: Fri Jun 12, 2009 3:48 pm
by Jim White
My CZ would shoot around 1 MOA when I first got it. After free floating and bedding, the groups really shrunk down to .25 to .50 depending on load and reverified at 200 yds.

HTH

Re: Group size question==need advoce

Posted: Fri Jun 12, 2009 5:08 pm
by glenn asher
We'll need to know a lot more details before we can even start to guess what, if anything, ails your rifle.

What bullets were you shooting, and also, the loading details (primer, case, powder, etc.)

What kind of rest are you shooting from?
How many rounds have you shot thru the rifle? A lot of .204s seem to need a couple hundred rounds to settle down and really shoot well.

Most, by no means all, CZs are decent shooters, by that, I mean under 3/4" @100 yards, from a solid bench, good scope, etc.

We need to know a lot more than the barest details before we can even try to diagnose the ailments.

Re: Group size question==need advoce

Posted: Fri Jun 12, 2009 5:51 pm
by Jim White
Remember too, all things being equal (gun, ammo, weather and shooter) .008" of movement at the muzzle equates to 1 MOA.

It doesn't take much....

Jim

Re: Group size question==need advoce

Posted: Sat Jun 13, 2009 5:34 am
by Doc One Shot
I know I have some work to do regarding loads, ect. This has a HS precision stock, free floated and alum. bedding. I was hopeing I could get 1/2 moa at some point.
Thanks

Re: Group size question==need advoce

Posted: Sat Jun 13, 2009 9:03 am
by Rick in Oregon
Doc: Every H-S stock I've got with the aluminum bedding block needed glass bedding to bring the rifle up to it's full potential. I've got a few of these stocks, and virtually every one of them performed better after proper bedding. The aluminum bedding block is not a cure-all by itself for bedding, and must be complimented with a proper glass bedding job to get full action contact with the stock.

My friend and Master Riflesmith, Darrell Holland proved this to me with one of my rifles....shot decent unbedded, shot bugholes once the alloy bedding block was glassed in with Accraglass Gel and the barrel floated with 2" of glass directly under the chamber area for barrel support on the action. I now bed all my H-S Precision stocks, and every one that has been done is a much more accurate rifle as a result.

Just a suggestion...... :D

Re: Group size question==need advoce

Posted: Sat Jun 13, 2009 9:20 am
by Jim White
Doc One Shot wrote:I know I have some work to do regarding loads, ect. This has a HS precision stock, free floated and alum. bedding. I was hopeing I could get 1/2 moa at some point.
Thanks
Doc,

Well, let’s started. I’m not one to assume very many things (gravity is an exception though) so if you’ve already done these things then we’re already ahead of the game. Basically, the way I see this is; its either a gun problem, an ammunition problem, a scope problem, a testing problem or a shooter problem. Only you can rule each one out.

Gun Problem;
- Is the action adequately secure in the stock (action screws)?
- Is the stock glass or pillar bedded?
- Is the barrel free floated (does it pass the dollar bill test)?
- What is the condition of the crown (very important)?
- What is the condition of the barrel?
- Is the head spacing within tolerance?
- What is the condition of the mounting rail for the scope rings?
- How many rounds down the tube?
- Was the barrel properly broken in?

These are pretty basic checks and with CZ’s reputation for quality, I’m sure most of these things are in good shape. However, bad cleaning techniques can ruin a barrel (the bore and/or the crown). The crown can be fixed, the barrel may be iffy. There may be other things that others could chime in with.

Ammunition Problem:
- Is it manufactured ammo or is it reloads? If its manufactured try another lot and/or another brand? If it’s reloads;
- What type of bullet are you using? From my CZ, the 40 grain is so-so. My Remington despises them.
- What type of powder? If its too fast or too slow, it may not do as well.
- OAL. My CZ has such a large jump OAL the distance off the lands may not matter.
- Adequate neck tension? Too loose, it can move when chambered, too tight definetly has affects on accuracy.
- Is your brass prepped (trimmed to proper length, primer pockets uniformed, flash holes deburred, necks trued/turned)?
- Is your powder charge consistent from round-to-round? If you’re using a powder throwing unit, some powders meter better than others.
- Are the primer pockets too loose?
- Is the case mouth beveled so the bullet isn’t deformed during the seating process?
- Check on the sensitivity of your powder from cold, mild to warm ambient temperatures. If it’s sensitive to temperature changes, make sure you’re testing in the environment you’ll be using the load in.

I may have missed some, so others may have more to add.

Scope Problem:
- Is it a good and sound scope? Good being defined by overall condition, not brand.
- Can the reticles be focused for you?
- Is there any parallax? If so, can it be adjusted out?
- Is it parallax free through the entire power range?
- Is the scope level?
- How is the eye relief, is it consistent?
- How are the scope bases?
- Are they tight and aligned to the bore? If not properly aligned, depending on severity, the scope is in effect being tweaked and it may not perform to its capability.
- How are the scope rings? Scope ring quality cannot be stressed enough. It’s what holds the scope in place and keeps it there.
- Have the rings been lapped?
- Are rings properly aligned to the bore? If not a single piece scope base may be in order although, I’m not sure there is a set up for the CZ in this manner.

Testing / Shooter Problem:
- What type of rest are you using? Take your time and set up the rest so that it, and you, fit one another. If you’re struggling (even, just a little) from shot-to-shot something isn’t right. I can’t begin to guess, how many times I see folks load testing and they’re fighting every shot to get it lined up properly.
- What type of target are you using for load testing? Make sure it’s big enough for you to see it properly. For 100 yards I use 2” Birchwood Casey Orange target dots and 3” @ 200 yards. This way, I can actually see where the cross hairs are in the black diamond center when the shot is released and, I don’t have to go to the maximum power of the scope to see the thing. Remember, you’re load testing, not testing your vision acuity. Shoot and see’s are OK for sighting in but I don’t care for them for load testing.
- Is the scope adjusted to hit dead center or off to the side? I choose off to the side so my sighting point is consistent and not altered by bullet holes. The down side is, when firing, make sure the rifle is leveled the same from shot-to-shot, otherwise any canting will throw the group off. On that note, make-sure the rifle is level (or canted if you prefer) the same for each and every shot.
- How fast do you fire your rounds? I shoot 1 shot every 60-90 seconds. In between I’m writing down notes (shot call, plotting placement, looking at the ejected case) and so on. If you fire too fast the barrel will heat creating mirage and by the time you see it, it has already had an effect. This is another thing I see a lot of, shooting to fast.
- How is your the stock weld and is it consistent from shot-to-shot? This is critical. Think of it as sight alignment. The CZ 527, unfortunately, has to utilize high scope mounts because of the bolt handle angle and the STD stock doesn’t have enough of a built in cheek piece to offset it. Maybe your HS stock does.

Again, others may have more to add because I’m sure I missed some. BUT…regarding gun, scope and shooter problems and as I mentioned previously, 0.008” of movement at the muzzle is 1 MOA down range. I know it was long winded but I hope it helps.

Jim