Buliwyf,
The CZ and the MRC action handle gas in much the same way at the outset which is to say they vent it. It is the manner in which the gas is vented which is the problem with the CZ (and the M70).
On the montana action the gas vent holes in the bolt body are aligned to direct gas into the mag well in the event of a cartridge failure. The gas vent hole (small)in the bolt of the CZ,like that of the M70 is located so that gas is vented into the left locking lug raceway. There is no vent hole in the receiver on the left side so the gas escapes by going along the left raceway, past the bolt sleeve and bolt stop and quite possibly, into the shooter's face.
Winchester addressed the shortcomings of the system by adding the little gas block which is retained by the extractor collar. One hopes that if this block is blown out it will be stopped by the bolt stop and sleeve and I think it would be. I actually like this gas block by the way both for it's part in gas control and because it prevents battering of the left locking lug under rapid fire bolt operation. I have retrofitted this part to my Pre-64s.
The CZ has no such block and the bolt sleeve is cut away to provide clearance for the bolt stop.
The bolt stop on the MRC action is located on the side of the receiver so that it does not interfere with the design of a bolt sleeve that effectively blocks off the raceway. Add to this the fact that most of the gas will be vented out the rightside (via the ectractor cut in the collar)and down through the magazine and the MRC action is better for sure.
For the M70 fans, I like the pre-64 M70 and always have but it is poorly designed from a gas handling standpoint. The new classic action has the little gas block but all the shortcomings of the earlier actions apart from that. It also has the two piece bolt which features a siver solder joint right in the middle of the cocking cam. Hard to put a positive spin on that feature!
The CZ is no improvement at all on the pre-64 except that the bolt stop is a little more robust. The inner collar is a positive feature as far as barrel fitting goes but does nothing for gas handling. Regards, Bill.

Thank you Bill. Your comments were an exceptional educational seminar.

I'm sitting here looking at a Browning FN LE Safari Grade. I guess the two big oval ports in the FN bolt work the same as in the CZ and M70? Also, what is the purpose of the small hole visible from the outside on the bolt handle side of the receiver on the CZ action. I think this small hole is on a M70 as well?

I hate to consume your time with these questions, but this subject is very important to me.

Thank you again.

Bob

Buliwyf---

The oval holes in a M-98 bolt direct gas into the left rail and then out the thumb slot. The CZ has a clearance slot in the left rail for the same reason.

Most all actions have a gas escape hole in the receiver ring. The Montana has two.

[ 02-12-2003, 21:52: Message edited by: JBelk ]

1894---

When you walk through the ACGG show and mentally inventory bolt action rifles on dispay the division between actions that look like a M-70 and look like a M-98 are just about exactly equal. Which one is picked by the customer depends on which *look* he prefers.

If you offered me my choice of a Granite Mtn or a Montana I'd take the Granite Mtn. If you offered me choice between one Montana and a dump truck full of La Caruna 1943s I'd take the Montana even if you offered to throw in the truck as boot.

Bad question.

1894--

I'm usually accused of causing head-on collisions, not side steps. Maybe I don't understand the question.

If you're asking ME what action *I'd* take it's still a bad question without enough information.

I have a craving for a Rhimakii Hornet and would love to find a K Mauser single square bridge for a 250-3000 and would probably trade a bunch of excess stuff for a two thirds scale Ruger #1 for just one more 22 K-Hornet(if such a thing was made), but other than that I already have all the actions I'll ever use with enough spares to scare me. I have no use for any more unless they'd be use for rifles for other people......and some people like Mausers and some like M-70s.

Full circle.

Mr. Leeper and Mr. Belk,

Just to revive this thread, I was wondering if either of you could comment on the earlier Sako L61R actions as to how they handle "gas". Being of a more or less Mauserish design, I would assume they behave in much the same way, but am specifically curious as to whether or not they can potentially dump alot of gas down the left raceway into the shooter's eye.

As always, thanks for your input!!

Bob

My view ( and that is certainly not the final word)is that the L61 is, like most pushfeeds, more of a "container" than a "venter". With a serious case failure though some venting has to occur. This is primarily via the extractor cutout in the bolt head and the ejector slot. Thereis a small hole on the left side of the receiver ring which is intended to vent excess gas. Some is bound to travel down the left raceway and some of this will be deflected by the bolt stop. In my mind there is no question that a flange on the bolt sleeve would be beneficial. I have to say though that of the guys I know who have pushed the limit in a Sako and had a case let go none have suffered any mentionable injury. The non rotating rib on the bolt prevents gas, brass, and the extractor from exiting the right side. Strangely the hole that vents gas from the interior of the bolt in the case of a pierced primer vents the gas through a hole in this rib and out the loading port. This is better than venting it into the locking lug raceway.
When it comes to blocking gas from getting to the shooter one of the best systems has to be the Savage 110. The stationary lugs used by Savage do a very good job of keeping everything up front.
In one case a 110 in 30/06 was fired with a caseful of what appeared to be Red Dot behind a 180 gr bullet (NOT a recommended load by the way). The rifle was ruined but from 6 feet away looked fine. The shooter was untouched by any debris. Pretty good gas handling by a rifle meant to contain the pressure. I'm quite certain that if this had been a pre-64 M70 I would have been dealing with a man who was at best partially blind. If it had been one of the better venting actions there would have been some pieces flying for sure but mostly in a safe direction. Keep in mind "safe" is a relative term in these cases.
So the answer from me is the Sako is pretty good as far as gas handling based on what I have seen. Regards, Bill.