CZ Combi gun troubles

Hornet 6

Well-Known Member
So I bought it last week, 12bore over .222, built in 92 but sold new in 2007 and taken back when owner lost his job
in early 2008 or so the shop tells me.
I bought the proper Kozap Q/D scope mount for it at the same time, at a horrendous price :doh:

I then set about loading some ammo to try it out, tried 23 grains of benchmark under a 50 grain Nosler BT.
Then the first problems showed up, badly smoked case neck and at best 2 holes (from 5 shots) in a 4 inch square target card at 100 yards.
Then tried 22 and 24 grains of Benchmark, no change, tried a different scope, a Swarovski 6x42, known to be good, no change.
Then tried Vit N-120 and several makes of 50 grain SP's and various charges from min to max, finally managed to get 3 from 5 on the card.
Bore is clean, crown looks good, gun locks up tight, shoulder is not blowing forward enough to suggest problems, but case neck stays sooty.
Can the collective think of anything else I can try before returning the gun to shop and trying to get my money back :oops:
Oh, tried full length sized once fired Sako brass, then just neck sized, also tried new PPU brass, as is, neck sized and full length sized.
Also tried loading to standard book length and .010" off the lands, crimped and un-crimped.
In desperation I also tried a few various factory loads, no better.

Neil. :)
 
mate had the same set up .......same results as yr self he part x 'd it for a s/g .it would not group at anything over 50 yrds sorry this dont help
norma
 
Three things come to mind:

Firstly, a weapon like this is always going to be a compremise, I have often thought about getting something similar just for checking around the park (in a 12g/.243) but have never gone through with it.

Secondly, how were you resting it for the test groups? I suspect this will be important.

Thirdly, I think that you will have to test it with some factory ammo before you can take it back to the shop otherwise the owner will simply blame your handloads!

Not much help but thats just my thoughts on it.

Glyn.
 
Glyn, factory ammo has been tried, Sako soft point and plastic tipped in 50 grain, PPU 50 grain soft points and some old Remington rounds, no idea what as not in a box.
Tried shooting from sticks, fence post, door mirror, sand bags and just held with my wrist resting on a sand bag, no change at all, or none that I could tell anyway.

Neil. :)
 
have you measured the once fired cases? do they differ markedly from the FL sized?
cant comment on the load for 222 but I am suffering a similar neck sootiness on a 243 load. only difference is mine groups very well.
but he load is low and not fireforming enough to seal the neck.
 
Cases measure up ok, and are almost identical to the the once fired cases I was given.
The soot is present on all cases no matter the load, including the factory ammo.

Neil. :)
 
I've a Brno 502.6 12g/.243 combination gun with a Simmons WTC 1.5-5x20 in a QD Kozap mount.

It shoots 2 MoA with everything and will go sub-MoA with one of my handloads...

BUT

It is very susceptible to hold -so I support it as close to the action as possible- and to heating up -so when checking zero I leave long pauses between shots. What hold are you using and are seeing signs of the POI climbing as you shoot a string?

I don't have problems with sooty necks, however. I'd have suggested changing powders, but if it happens with both Benchmark and Viht N-120, this might not help. In any event 22 grains of Benchmark under a 50-grain BT already looks to me like a hottish load, so I might try dropping back a grain. You don't mention how many grains of Viht N-120 you're using, but Quickload suggests anything above 20-grains is likely to be a bit lively.

Finally. What kind of results do you get over the open sights? I ask because it's just possible the clamps on the mount aren't adjusted so they're repeatably tight on the rail.
 
Scope mount is properly adjusted, and tight.
I have loaded with both powders from low to maximum load, with several different 50 grain bullets, and even some 40nosler BT's, as well as 40 and 45 grain speer soft point.
As for hold, yes I supported it as close to the action as possible, by hand and on bags.
I even tried two sets of sticks, barrel has not been allowed to heat up while shooting, there is no rhyme or reason to the groups, all over the place best describes it, with no shots closer than an 1 1/2" apart, usually more, much more.
As I'm working tomorrow and the shop is shut on mondays I shall return it on Tuesday and see what he says.
If it comes to it he can keep it and try for himself, take a few weeks as far as I'm concerned as I just don't want
to go through all the paperwork for a variation again less than 10 days since the last go round.
To cheer myself up I have now had a couple of cans of Stella, removed the Swarovski 6x42 ready to fit it to my .22lr :lol:

Neil. :)
 
Last edited:
Hello Neil why would you buy such a thing in the first place as it sounds like a compromise gone too far and how is your shoulder and I hope it wasnt caused by strenous sexual activity,Lee
 
Hello Neil why would you buy such a thing in the first place as it sounds like a compromise gone too far and how is your shoulder and I hope it wasnt caused by strenous sexual activity,Lee

Why, because I wanted a one gun solution for walking round the lakes, capable of taking fox and Canada's (.222) the shotgun bit for rabbits ducks etc.
Strenuous sexual activity, I (very) vaguely remember that :rofl:
No it was caused by an over eager nurse who was supposed to be just slightly opening the shoulder joint so a bloody great big needle could be inserted, he went a bit to far and popped my left shoulder right out, aches a bit but thats all now, was only out for maybe 2 minutes.

Neil. :)
 
It might be worth having a close look for damage or poor finishing at the crown before you give up on it.
Sinbad
 
It might be worth having a close look for damage or poor finishing at the crown before you give up on it.
Sinbad

The very first thing I looked at, with a magnifying glass, it is fine unfortunately, as at least that is an easy fix.

Neil. :)
 
I sent you a PM on PW regarding the mounts....

It's sad to hear you're not doing well with the gun. They don't seem to be as accurate as a regular rifle but mine works ok. I've shot more Deer with it than any other rifle I've ever owned and I haven't lost one to it yet. All the shots seem to land vaguely where I point them even with the iron sights!

I hope you get a refund easily enough. That sort of performance isn't acceptable even from a combi.

For those who have said that they are a compromise - well maybe, but in some situations you have to compromise even more by taking just a rifle or shotgun out. One thing I can say with 100% honesty is that I spotted more Deer when out with the shotgun and more Squirrels when out with the rifle before I had my combi. Now I have a combi I generally see **** all but if something does turn up at least I can shoot it!:smug:
 
Hmm. I tested one of these, new, 12 bore over 223 for Shooting Times in the 1990s when I used to do shooting tests and reviews freelance for the gun press.

Mine was equipped with the correct factory made, one piece, 'scope mount and could stay on a rabbit at one hundred yards with factory, Federal, 223 soft point.

So my theory is this IF IT DOESN'T WORK WITH FACTORY AMMO:

You 'scope or 'scope mount is defective.

Your bullet weight or the length of your bullet is too "different"...in that the rifling twist may be "all 1990s", in other words based around 55 grain soft point bullets, and thus the pitch wrong for the bullets you are using.

Yet you say that you are using 40-45 grain bullets with some 50 grain?

I suspect that in fact these 222 BRNO guns may just be 223 BRNO guns with chambered with a 222 reamer rather than a 223 reamer. One size and twist of barrel in that diameter "fits all" as it wer.

In which case I'd use something that uses a bullet more common in factory 223 in the 1990s. That is a 55 grain soft point. No fancy plastic tips and all that just plain soft point. It may work?

So I would try factory 55 grain soft point ammunition and if it doesn't hold under 4" at 100 yards would ask for a refund.
 
Last edited:
Well it was made in 1992, as a .222 with a 1 in 14 twist barrel, I have used a few 55 grain Nosler soft points, and 53 grain V-max no different.
The scope, well two scopes, a know to be good Nikon ProStaff 2-7x32, and known to be good Swarovski 6x42.
Scope mount, the Kozap mount is the original mount made for Brno/CZ and imported as such by Edgars.
The only other mount I found is the Apel one at 300 euros' shipped, and it's the same thing, lever mount base with bolt on rings like opti locks.

Neil. :)
 
Then the first problems showed up, badly smoked case neck and at best 2 holes (from 5 shots) in a 4 inch square target card at 100 yards.
Also tried loading to standard book length and .010" off the lands, crimped and un-crimped.
In desperation I also tried a few various factory loads, no better.

A few questions.

1. Does the factory ammo also have excessive sooting?

2. How do you know you are 0.010" off the lands, by what means have ou determined this?

3. How long are you leaving between shots? Some combination guns have thin barrels barrels, designed to fire only one shot.

4. Are you shooting from a bench, using fore and aft sandbags?

Exessive sooting occurs when the cartridge does not expand sufficiently, or sufficiently quickly, to seal the chamber. Combination guns can have a long free bore. This results in lower peak pressure than in barrels with a short freebore. This is deliberate beause the standing breech (shotgun style) action is not as strong as a turn bolt action. It could be that you have a long freebore and in consequence the pressure is insufficent to obturate your cartridges properly. If that is the case then you will have to increase, not decrease, the charge of propellant or use a different powder.

I have a Valmet 412 in 12/243 and the freebore exceeds 1/4 inch. That said, I have not noticed the problem you describe. I have experienced the problem in a turn bolt .243 rifle when I switched from 100gr bullets to 70gr bullets after approxiamtely 1600 rounds. The freebore in that rifle had increased to over 0.100" and I had to both seat the 70gr bullets out a long way and increased the charge by three grains above the stated maximum load before the sooting stopped.

As for the accuracy issue, try shooting the rifle at 25 or 50 yards using the iron sights (I presume it has iron sights) supported fore and aft. A back bag can make a tremendous difference to group size. :)

I hope this helps.

-JMS
 
Free bore is not that long, a 50 grain Nosler loaded out to the lands is 2.243 OAL, I have loaded out to within .010" of that.
(how I found that, size a new case to only just hold the bullet, drop bullet down the hole followed by the case, shut gun, open gun lift the round out and measure.
Bench and bags is a yes, left anything up to 30 minutes between shots, but at least till cold to the touch at the chamber and in front of fore end.
Soot is just as bad on factory ammo.

Neil.
 
Back
Top