Accuracy problems with CZ550 in .375 H&H

[Nic7-300wsm]

I have problems getting my .375 H&H to shoot below 2" groups at 100 meters. I have now tried almost everything; free floating the barrel (except for recoil lug under barrel), fully glass bedding the entire barrel, only bedding the lug section of the barrel.....
My next option is to remove the recoil lug under the barrel and perhaps add an additional cross-bolt in the stock....this whole lug under the barrel doesn't make sense??? You are creating a pressure point on the barrel, not good for accuracy.

I have shot several groups that 3 rounds print sub-MOA, but the following 2 shots open the group to above 2". I have tried this with cold barrel (one shot and wait to cool), warm barrel (5 shots consecutively), even 2 shot, cool, 2 shots, cool, one shot.... No consistency, even shooting the same load following day had different group size...

I have used 220gr Impala bullents, 270gr hornady and Barnes, 286gr solids, 300gr SP and 300gr Hornady DGX. All have same issues, no consistency in groups.

Any info or help is welcome!

 

[PHOENIX PHIL]

You didn't mention anything about powder. Were all these loads with one powder?

 

[TokkieM]

I have owned both the Brno ZKK and CZ 550 Magnum in 375 H&H,accuracy was never a issue. Can't see that the front F-block could be a problem unless it is not square or the lug on the barrel is not square. I also doubt that the rifle will go from sub MOA to 2 MOA without reason.
Sounds like you have had the rifle in and out of the stock a bit,one of mine was particular about how I tightened the action screws,had to tighten the rear screw down hard first before tightening the front and barrel screw.

I would start by checking the basics,action screws (thread on the barrel lug slot tends to get cross wired and although it feels like it's tight it's just threaded up) scope and scope mounts too,just to eliminate them. You mention the bedding and I would suggest stripping the whole rifle down and checking everywhere that no bedding compound got into the action,had FN with a small small piece of compound stuck in the extractor pocket down in the action,played havoc with accuracy until I removed it.
Would do a proper cleaning job on the barrel at the same time.

As and afterthought you may also want to check the barrel crown for damage.

Hope you get it sorted.

 

[bassasdaindia]

I have problems getting my .375 H&H to shoot below 2" groups at 100 meters. I have now tried almost everything; free floating the barrel (except for recoil lug under barrel), fully glass bedding the entire barrel, only bedding the lug section of the barrel.....
My next option is to remove the recoil lug under the barrel and perhaps add an additional cross-bolt in the stock....this whole lug under the barrel doesn't make sense??? You are creating a pressure point on the barrel, not good for accuracy.

I have shot several groups that 3 rounds print sub-MOA, but the following 2 shots open the group to above 2". I have tried this with cold barrel (one shot and wait to cool), warm barrel (5 shots consecutively), even 2 shot, cool, 2 shots, cool, one shot.... No consistency, even shooting the same load following day had different group size...

I have used 220gr Impala bullents, 270gr hornady and Barnes, 286gr solids, 300gr SP and 300gr Hornady DGX. All have same issues, no consistency in groups.

Any info or help is welcome!

NIC - welcome are you in SA ?

 

[Nic7-300wsm]

You didn't mention anything about powder. Were all these loads with one powder?

No, I have used different powders....S341, S335, S355 (all South African powders) with CCI250 and CCI200 primers.

 

[Nic7-300wsm]

NIC - welcome are you in SA ?

NIC - welcome are you in SA ?

Hi bassasdaindia, yes I am in SA...

 

[bassasdaindia]

Hi bassasdaindia, yes I am in SA...

PM sent

 

[Nic7-300wsm]

I have owned both the Brno ZKK and CZ 550 Magnum in 375 H&H,accuracy was never a issue. Can't see that the front F-block could be a problem unless it is not square or the lug on the barrel is not square. I also doubt that the rifle will go from sub MOA to 2 MOA without reason.
Sounds like you have had the rifle in and out of the stock a bit,one of mine was particular about how I tightened the action screws,had to tighten the rear screw down hard first before tightening the front and barrel screw.

I would start by checking the basics,action screws (thread on the barrel lug slot tends to get cross wired and although it feels like it's tight it's just threaded up) scope and scope mounts too,just to eliminate them. You mention the bedding and I would suggest stripping the whole rifle down and checking everywhere that no bedding compound got into the action,had FN with a small small piece of compound stuck in the extractor pocket down in the action,played havoc with accuracy until I removed it.
Would do a proper cleaning job on the barrel at the same time.

As and afterthought you may also want to check the barrel crown for damage.

Hope you get it sorted.

Thanks for advice on the screws, will try that. I have almost done everything else... did a real proper job cleaning the barrel, re-crowned the barrel and clean and cleared all compound everywhere. I am now going to try to really tighten the action and recoil lug screws, without the barrel screw as I have removed all bedding material in the stock, except for the bedding done around the chamber and recoil lug. the F-block is also bedded into the wood and is 100% square with the recoil lug on the barrel.

 

[colorado]

I've got what I believe is a CZ 550 McGowen barrel (since I bought mine from the CZ Custom Shop, but I'm not sure) in 375 H&H leaning against a wall. It shot well under MOA. My rifle has since been rebarreled to 500 Jeffery. If you were in the U.S. I'd ship it to you. I have no idea what the laws are to ship it out of the country. I haven't looked at it in awhile, so I will, but I cleaned it and oiled it when I got it back. That being said, almost everyone who has a CZ have had no issues with accuracy. Best of luck to you.

 

[thi9elsp]

I use Federal 300 Grain softs and solids. The softs print an inch at 100 yards using the set trigger. The solids also print a similar group, but two inches lower than the softs and a 1/2 inch left. All of this is using a Leupold VX1 1-4X20 with Warne Rings.

 

[8x68]

I've got what I believe is a CZ 550 McGowen barrel (since I bought mine from the CZ Custom Shop, but I'm not sure) in 375 H&H leaning against a wall. It shot well under MOA. My rifle has since been rebarreled to 500 Jeffery. If you were in the U.S. I'd ship it to you. I have no idea what the laws are to ship it out of the country. I haven't looked at it in awhile, so I will, but I cleaned it and oiled it when I got it back. That being said, almost everyone who has a CZ have had no issues with accuracy. Best of luck to you.

Barrels are regulated by ITAR. You would need to fill out a DSP-5 application and use the one time exemption option. It would then have to be sent to the State Dept for them to lose it. This will go on for a couple of times until you get pissed off and tell them to cut the crap and stamp the application. They want to keep aggravating you to the point where you give up. I don't give up. Yes I went through it exporting a Marlin 30/30 deer rifle from the US to Canada. It would have been quicker to drive to my dads (who had the rifle) pick it up, drive to the Canadian border, declare it, pay the tax and that would of been it (unless I got spot checked by a US CBP officer before the border...then that wouldn't of been it.). But oh no I had to try and do it by the book. I figured out that the State Dept don't like guns. It took 18 months to get it here.
If it's going to another country I would suggest the recipient looks into what the import procedures are. (some countries like to have a big padded envelope accompany the item as it makes things go smoother

 

[8x68]

Thanks for advice on the screws, will try that. I have almost done everything else... did a real proper job cleaning the barrel, re-crowned the barrel and clean and cleared all compound everywhere. I am now going to try to really tighten the action and recoil lug screws, without the barrel screw as I have removed all bedding material in the stock, except for the bedding done around the chamber and recoil lug. the F-block is also bedded into the wood and is 100% square with the recoil lug on the barrel.

Did you try using iron sights at 50m & 100m? Do you have the same issue? I was having a similar problem with several of the larger calibers I have and it turned out it was me. I'd shoot two or three rounds that grouped well and then for some reason I'd have a flier or two. I had someone watch me shoot and I was told I was flinching every so often.
What are you using for a rest to shoot from?

 

[BWH]

To establish somewhat of a "baseline".... have you considered using factory ammo? See if you can get some consistency... Just a thought.

 

[BRICKBURN]

I have problems getting my .375 H&H to shoot below 2" groups at 100 meters. ....................

I have shot several groups that 3 rounds print sub-MOA, but the following 2 shots open the group to above 2". ........

This contradiction begs a question.

You shot 3 round groups sub-MOA. So, how did you do it? Details.

Before you blame the gun, have someone watch you or video tape yourself shooting. (or both)

It has taken me some time to learn how to shoot my CZ500 .375 at targets to get tight groups. It has to be held differently than my other calibers.
When I am consistent, the rifle shoots very well.

 

[ornery]

Speaking professionally, with all of the above work completed, Brick is correct on the next step. One of the most difficult ponds I have had to dive into is operator error. There are rifles that some of us shoot well and others do not. Is it a "hogback" stock or a straight one? I shoot the dropped comb style much better that the straight, myself.

Optics mounting and attendant problems should be studied carefully. You did not mention the optic itself. The iron sight test is a good option.

You're getting good advice here. I would check all of these things were you to bring it by the shop. How did it shoot before you bedded it?

 

[Red Leg]

If I read this correctly, and you are getting the first three shots to go MOA to sub-MOA and they are consistently doing so, then you might consider simply declaring victory.

 

[gizmo]

???? I don't know buddy, I've got a 375 CZ 550 and it's a tack driver day in and out. I haven't shot it a whole lot as I've only had it for a few months but I have been highly impressed with the rifle. Best of luck. I hope you didn't get a lemon and can figure it out soon.

 

[CAustin]

Good luck to you! This seems like a quandary.

 

[BRICKBURN]

If I read this correctly, and you are getting the first three shots to go MOA to sub-MOA and they are consistently doing so, then you might consider simply declaring victory.

Hence my confusion.

 

[enysse]

I'm confused too, I would have a experienced friend watch me shoot and make suggestions. Or have someone else shoot the gun and take the shooter (you) out of the equation.