Harald Wolf of _Hatari Times_ says that many PH's in Africa are simply rechambering the CZ 550 Safari Magnum in 458 WinMag to 458 Lott. A practical stopping rifle.

I say the push feed modification of the CZ 550 Magnum extractor need not be done. If it aint broke, don't fix it.

Let us say you have simply rechambered a 458 WinMag to 458 Lott in the CZ.

You load 5 into the magazine easily with room to spare, but not enough for the sixth cartridge. But you want to have a six shooter.

Never fear. Use the bolt release to slde the bolt out of the action. Slide the sixth cartridge into the bolt face, and replace the cartridge and bolt as a unit into the action, hold down the cartridges in the magazine, and slide the sixth cartridge into the chamber.

Now go hunting with the gun on safe.

To recharge in a hurry you will be limited to 5 in the magazine, all CRF. No pushfeeding. No problems. Original Mauser 98 style faultless.

KISS principle. No need to reshape the CZ extractor. Notice how nicely the feed ramp is polished on those CZ's straight from the factory? I am even starting to like their stocks. They kind of grow on you. Thanks, Czechs!

------------------
RAB

I don't think I understand this. To my recollection you can push feed that first round in the CZ without altering the extractor but I better go try it. Maybe it was the Ruger.

Getting the 6th round in there by extracting the bolt is a good idea, but I wonder if I could manage that in the dark. I guess you wouldn't have to push the top round in the magazine down when feeding the 6th round, would you? I better go try this.

Converting the CZ 458 to a Lott is fairly easy. Even I did it and there is a court order against me using hand tools!

Will

The extractor needs not be reshaped, just a little polishing is necessary. CZ claims their extractor should be able to push feed. I would take some cloth and Rem Clean before trying something else.

For top loading: I fill up the mag, then depress the top case slightly and slide one more cartridge in from the side, under the extractor. Then I close the bolt a little, so the top case will be downpressed, and then I simply close the bolt. No stress, as the rim is already under the extractor.

No separate bolt. If there is sudden trouble I remove the round to be fumbled and just close the action. In 9.3 this gives 5 rounds anyway.

Hermann

------------------

Are you saying you can not drop a cartridge into the chamber and close the bolt? If so, your extractor needs attention.

While its a regrettable practice, all of my CZ550's will chamber a round ala push feed. This is not a good practice and yes I've seen two broken Mauser extractors caused by folks forcing a cartridge snap over. With that said ,taking the bolt out and placing a cartridge on the bolt and then replacing the bolt is getting a bit extreme! But technically better than pushfeeding IMHO.
I continue to believe and have seen enough evidence to convince me that Mauser type actions were never designed for push feed and that continuing to do so will eventually result in breaking or tweeking the extractor.Interestingly, when I have modified an extractor to allow for pushfeeding, I have sporatically observed failures to extract. This of course will happen at the worst possible time according to Murphy's law. Finally, I just can't imagine the situation where I will need that sixth round without adequate time for reloading.
Anyway It's fun to restart the grand argument of thw How's and How nots of Pushfeeding Mausers.-Rob

Rob,
I agree with you. I guess I learned something the last time this discussion went down. My five-shooter becomes a six-shooter only if I have leisure time to fiddle with it.

------------------
RAB

Most CZ's rechambered from 458 win mag to 458 lott will not feed soft points without a bit of ramp work.

500grains,
Then until fully functional, no softs in the magazine, only solids. One soft up the spout and a magazine full of solids until those gun kinks are worked out, or found to be a non-issue. Fingers crossed.

------------------
RAB

Will,
You must be semi-retired to be able to find time to do your own rechambering.

I am going to have to get a real life again soon.

Oh yeah, my _African Hunter_ subscription will likely start off with the current issue, with your elephant hunting adventure. 10 to 12 weeks on the slow boat from the dark continent.

------------------
RAB

[This message has been edited by DaggaRon (edited 04-16-2002).]

Are there really two camps here? Why would you not desire a DGR with direct hand-to-chamber loading capability? When done correctly, there is little stress involved. I see it as an absolute must for the hunting of dangerous game.

Two weeks ago I was playing with my CZ550 in 500A2 converted from a.416 Rigby. To get it to feed softs properly all that needed to be done was to widen the ramp and massage the rails. The CZ550 ramp has two triangular "wings" on either side of the ramp into which the soft point will unfortunately be directed. By carefully filing the rails and these triangular wings and carefully observing how the cartridge enters the chamber I was able to achieve absolutely flawless feeding. Polishing the rest of the ramp made it even slicker. Oh, by the way, for the doubters out there, it also ejects flawlessly. The 458 win Mag to 458 Lott should be even easier to make work.-Rob

Nick,
I am somewhat ambivalent about it, but am leaning to the original Mauser CRF only.

A pushfeed action is designed for pushfeeding, but the original Mauser was not.

CRF is easier on the brass than the pushfeed of whatever type, even if the difference is minute.

But, the ability to slip one up the spout by fingers might save your bacon if the magazine is hopelessly nonfunctional (for whatever reason) but the bolt still works, extracts and ejects.

However the modified Mauser extractor just might be more prone to the occasional failure.

I see no end to the argument either way.

So ... ???

------------------
RAB

Dagga,

Obviously, under the right circumstances, that is a very good idea. I will file it away for future use. Thanks.

However I am a bit upset that I didn't think of it.

------------------
Wendell Reich
Hunter's Quest International
wendell@huntersquest.com

[QUOTE]Originally posted by DaggaRon:
Hi Ron,
My CZ 550 action that I built my 470 Mbogo on will close over a chambered round very easily. There is no excess force required similar to the Ruger 77MK11 416 Rigby action that I have. I like the idea of being able to throw a round in and close the bolt. I have a 602 that will not do this and it is obvious that it will not as soon as you start to move the bolt down. I wonder if Bruno hasn't relieved the receiver to allow the extractor the freedom to do this.
Rob:
How much bevel do you put on the back of your barrel after you have chambered it. The bevel I'm refering to allows the cartridge a bit more guidance to enter the chamber after travelling over the feed ramp?

470 Mbogo

DaggaRon - There is NO argument ... I just finished putting a ridiculous amount of time and effort fitting an extractor to allow top feeding on my Gibbs (CZ-550). Then to read that some knowledgable guys like you and ROB didn't want this capability sort of threw me some .. that's all. My 602's and CZ-550 have all allowed push-feeding BTW,except for the Gibbs rifle, which I attributed to the jumbo headsize.

470MBOGO- You just got to stop giving away my secrets! I put a slight bevel on the edge of the chamber about 5-8 degrees or so and polish it. It's no cone, but helps alot. By the way, I finally got the Pac-Nor .475 barrel and an action is on the way. I still have not deceided if I'm going to use a CZ550 or a 1917 Enfield. So another 470 MBOGO will soon be born! I'll knock this out once I get back from the shoot in Reno-Rob

470Mbogo, Rob, Nick,

Some of them will do it with a lot of force and damage to the brass. My gunsmith can handle it if I want to pushfeed the Mausers. I am ignorant. Relief inside the receiver ring or shaping of the extractor, or both? How about the proper technique, anybody want to reveal the secret? I have known about the slight bevel of the chamber edge. I insist my gunsmith do this for my barrel jobs. I hate scratch marks on the brass.

Nick, I assume you can only get 3 of the huge 505's in the magazine, so I think I would opt for pushfeedability on the fourth round in the chamber too. What did your conversion to the new extractor entail? Did you do it yourself or get a gunsmith to do it?

I am ambivalent as hell about this. Just switch extractors for the mood of the day?

------------------
RAB

[QUOTE]Originally posted by DaggaRon:
Hi Ron,
My CZ 550 does this just the way it came from the factory. I posted this months ago to find out if the factory had actually produced the action this way or if I just got lucky. I was wondering if they opened the reciever ring to allow for this movment required because I've had absolutely no problems with extraction. I like the idea of a four shot 470 Mbogo. That's a hell of a lot of fire power.
Take care,
470 Mbogo

Longish story DaggaRon. When all was said and done the original extractor (.375)was probably O.K. but the brass I bought was so irregular as to rim thickness the extractor simply could not handle the full range with full reliability.

Not realizing all this at the time, I went through 2 more extractors (.416 Rigby), 3 gunsmiths and some rifle shipping costs, without satisfaction.

Now, with pangs of frantic desperation, I purchased 2 .458 Winchester extractors, at the suggestion of Mike @ CZ-USA. Upon receipt of some email tips from John Ricks, I proceded to fit both extractors myself in an hours time. All this, in tandem with the arrival of some new "HDS" cases, has made life good again.

What about pushing the Mauser type extractor towards the center of the rifle while puhfeeding a Mauser type rifle,(to help the extractor over the caserim) , this would in any case prevent broken extractors from forcing a "nonpushfeeding" mauser action.

S

Shadrek,
Yes, if you mean depressing the extractor forward of the mount with the thumb so as to relieve pressure at the hook. You will, sometimes, hear it click off the case rim and on into the extractor groove. I am making a little habit of this when top feeding the extra round.

Good point Shadrek and Nick, ditto.

My impression is that all that needs to be done for the pushfeed modification of the Mauser extractor in most cases is to slightly bevel and polish the leading edge/face at the inferior/lower corner (a radiused profile/contour is there already) on the front surface of the extractor, at the point where it first contacts and slips over the rim when pushfed. I have never heard of any modification inside the receiver, but have wondered about this as 470Mbogo suggested. Presumably the extractor cut is not a close tolerance thing at all, and there should plenty of room for play there, as when flexing the extractor slightly to help it snap over the rim.

If the modification is done properly, the back side of the extractor is untouched, and its "footprint" on the rim of the brass is unchanged ... then surely extraction should be as reliable as it was before the modification.

These are the ramblings of an amateur. I have never fully satisfied my self on this issue, so throwing it out for review AGAIN may be helpful for others as well as me.

Am I going to have to pester my gunsmith in Knoxville Tennessee about this, or will someone dare divulge any more specific instructions? For educational purposes.

------------------
RAB

Both my CZ 550's and my Brno 602 will allow me to single feed with no problems extracting and no damage to brass. For all you 550 guys out there, I talked to the factory rep in Kansas about the plastic followers and he said he would exchange them for steel ones. Will have them back in stock in June. Cobalt

Cobalt,
I believe they (CZ's) all come from the factory supposed to do this. Some may be a little rough and require tweaking to function smoothly in pushfeed mode, but are easy to straighten out, as I just did with my 458 Win.Mag. It now CRF+PF's just fine, fine as frog hair. Just a little light polishing of the extractor at a very small point, and now it works fine. I like the CZ, warts and all! It's ills can be cured!

Most of the problems having to decide between CRF only or CRF+PF extractors come when opening up the bolt face, like from the 375 to the 416 Rigby size, or even 505 Gibbs as with Nick.

All my CZ/BRNO/BBK rifles will pushfeed now except the 510 JAB which started as a 375 H&H BRNO ZKK 602. Firing the 4.75" long loads with the 750 grain Hornady A-Max in it requires that I operate it like a shell holder action anyway, but it CRF's the hunting loads from the magazine.

I am simply agonizing over conversion of the last of my CRF only "Mausers" to CRF+PF. I have done it with all the others. Guess I ought to be consistent, eh?

So, my unofficial, unlearned, somewhat reasoned take on this: I don't think it is a problem in any way to add PF to your CRF. Take your pick, CRF only or CRF+PF. If done properly they are both reliable. Just be consistent in your habits, and I shall, if it involves a hunting rifle.

------------------
RAB

Ron,
Have you shot the 705gr AAA Ammo Semi-Boreriders yet? If you haven't, no big deal. I'm just curious.

I'm ordering a McMillan stock for my CZ conversion. I just can't stand the factory stock. Have a good one.

ps. Edited per your wishes ;-)

[This message has been edited by BMG (edited 04-18-2002).]

DaggaRon- I just feel compelled to say that I will bet you a case of beer( your choice) that if you push-feed your CZ550, enough, you will experience a failure to extract or a broken extractor. 1000 times for sure should settle the question with different cases of course. I'd even be pleased to be proved wrong! I think a while back I went over the exact mechanical reasons why I don't believe this is a good thing to do. You can get away with it for awhile, but it will eventually fail. It's sort of like speed shifting a corvette, It works fine for awhile, then things break because it just wasn't designed for those stresses. In any event just keep a spare extractor handy.
By the way we had great laughs at the local range last week when a guy blew his cool trying to push feed a custom Mauser he had just bought and could not get it to push feed. He was trying to force it and eventualy tweaked the extractor leaving a round in the chamber and we had to rod it out for him before we could let him off the range. He just could not believe his expensive Mauser was not going to work just like his Rem 700.-Rob

BMG,
I swear I am going to get it done this weekend, along with some 470 NE and 375 RUM. Just a light load of 110 grains of IMR 4350 for the 705 grain AAA's in the 510 JAB. I am back home in Kentucky for good now, I hope. I am off the road and should have more opportunities to play if not working too hard. I am just now getting caught up on some family, work and tax related stuff and the honey-do list. I will report back to you after the weekend range session.

Rob,
I hear you. I think the solution for us hunters is to have the capability to PF in an emergency, but to stick to CRF routinely. If a full chamber and a full magazine are required, then do the shell holder routine or fiddle the other cartridge into the boltface, as the rifle/cartridge/fingers combo permits it, for CRF plus one.

The extra stress on the extractor comes from the torquing to snap over the rim. This should be avoided to reduce wear and tear, eh?

Still, there is nothing wrong with the PF modification of the extractor, as long as you don't use it except to save your bacon. Minimize the stresses by avoiding the PF and sticking to CRF otherwise. Am I right or am I wrong?

------------------
RAB

Rob,
What you say has merit but so does being able to push-feed. Instances where a round may fail to extract (more often eject) occur because the claw is riding on the rim, rather than snapping over into the groove.
This can be checked by pushing on the extractor, as described above, and/or performing a partial extraction, just to take a visual. When a push fed cartridge is actually fired, I believe the claw will snap into the groove every time. It is an agonizing scenario, anyway you look at it.

Doesn't the CZ have a hinged floorplate on the magazine. I have never looked at one so I cannot say. But, on my Ruger 77 416 Rigby when I want a "full load" I feed one in from the mag, turn the rifle over and fill the mag from the bottom. A whole lot less trouble than taking out the bolt and all that stuff. Of course, if the CZ has a fixed floor plate, that makes this kind of impossible doesn't it?

Big Bore,
The CZ has an excellent release button on its hinged floor plate, but if you release the spring tension by opening the floor plate, the precisely aligned cartridges may shift when you place another cartridge on the pile from below and close the floor plate on the disarray in the staggered box. If it was a single stack magazine, your method would work without regard for the stagger and possible jam production. Load through the magazine and feed from the magazine whenever possible. Pushfeeding from above the magazine is an emergency measure with a Mauser type system. Shell holder or fiddle finger loading from the top is a leisure activity, after the magazine is full.
The floor plate shouldn't be opened except to dump everything clear of the box.

When you are topping off a Ruger 416 as you describe, you only have two of the fat Rigby cases in there and you are adding a third to fill the box.

The CZ magazine is minimally bigger than the Ruger (I have one of each in 416 Rigby),and if you are filling it with H&H case size cartridges in another rifle (such as 458 Lott), you are adding the fifth to the pile in a relatively bigger box, and they will lose their alignment when you do the above procedure.

I can easily do the same as you with my 416 Rigby Ruger or CZ, but it is extremely hard to do the same with the smaller cartridges. It would be prone to produce a jam in any rifle, and may be how some of these mysterious safari jams happen.

------------------
RAB

[This message has been edited by DaggaRon (edited 04-18-2002).]

You know, even in an emergency, I think my natural reaction would be to dump a round in the mag, press it down and slam the bolt home. It's just as fast as trying to push feed! I have just never gotten comfortable with push feeding a Mauser due to my past experiences, and my fear of a stuck round. Believe me, I have tried a bunch of times to alter Mausers for reliable push feeding, I've played with various extractor bevels, bevelling the chambers edges, relieving the inside of the extractor to allow more collar movement, even reshaping the extractor etc. Each time I end up in exactly the same place. Feed a Mauser from the magazine for reliability. I too thought for awhile that an extractor hung on the rim will snap-over on firing. Twice it failed to do so.This was as recent as two weeks ago when I was building a 9.3X64 and wanted to see what it would take for me to get reliable push feeding. Oh, it looked great and worked almost all the time, but then at the range I had two failures to extract.
When I face ol MBOGO again it will be with a CRF Mauser fed from the magazine. I just love this discussion as it always gets my blood going!-Rob

Ron,
Please chrony those loads if you get the chance. I'm curious as how they vary in fps as opposed to a 700gr M2 Ball or M2 AP.

In my BMG, I could only get them up to 2950fps with a 30" barrel and H50BMG. I was working up loads and at 231gr I got 2950fps, at 233gr I got 2940fps, and finally at 235gr I got 2935fps. I think that the extra powder was being blown out the barrel before all of it got a chance to burn. I've never had pressure signs with the 705gr bullets.

Thanks for the info,
BMG

ps. Edited per your request ;-)

[This message has been edited by BMG (edited 04-18-2002).]

BMG,
Please call me anything but that. Ron, RAB, DaggaRon, anything but Dr. Berry! I'm just another gun nut around here. And, I am not spying for the anti-gun AMA.

I will add some of the 700 grain M2 ball and AP for a comparison at the same charge of 110 grains of IMR 4350 in the 510/460 Long.

Now I must vamoose for a while if I am to catch up on things besides this fascinating website.

------------------
RAB

Rob,
I see your point. I hope we get more input on this subject.

Gentleman ,I like to share my views on the CRF debate.

I have 2 602�s and nether will push feed and I am glad about that for the simple reason that if the extractor won�t slip over the rim going in it won�t slip over coming out.
I don�t have a 98 Mauser on hand (I foolishly sold it) but if I am not mistaking the little dovetail arrangement on the front of the bolt the one that arrests the extractor hook can only be installed one way and will not allow the extractor to be pulled side ways and therefore won�t allow push feeding.

I checked the 602�s and this dovetail arrangement has the rear section flush.
This will do 2 things it will allow the extractor to move back and forth in a lateral direction so if we push feed ,the cartridge head will push the extractor rearwards and also the dovetail , thereby creating enough clearance for the dovetail arrangement to be lifted out of it�s retaining groove when the extractor bends to slip over the rim.

In the BRNO set up (half a dovetail) one has still the same effect as the 98�s because when extracting a case the extractor is being pulled forward engaging the half dovetail .

I am sure after my miserable attempt to explain all this it will be a clear as muddy water all of you however what I want to say, I don�t want my extractor to bend and with a little practice it is no problem to top the rifle up by slipping the rim under the extractor.

Talking about extractors on my new LH M70 Winch. there is no dovetail what so ever.
There was article in Rifle I believe about a smith that overhauled M70�s.
In there it was stated that the extractor of the M70 is not made of spring steel and can be bent like a piece of mild steel,now this combined with no dovetail is not good at all.
This smith was replacing them with a spring steel after marked one
The question is where did he buy them???

Regards Martin

I know the discussion is about the Mauser action, and the Win mod 70 is a derivative of that design, but I thought I'd throw this in anyway...

The Winchester user manual (Safari Express) recommends filling the magazine and then dropping a round into the chamber and closing the bolt for those times when you want a full mag + 1.

Rick.

Well,
I am learning. Thanks, Martin, for pointing that out. Stuart Otteson's book, _The Bolt Action_, deals with this "dovetail arrangement." He calls it a "tongue and groove" arrangement, and has a nice little drawing, "Mauser M98, bolt head details" :

"The claw doesn't rub or cut the cartridge rim during bolt lift, and extraction force acts as a straight pull. A tongue working in a narrow groove just forward of the locking lugs anchors the extractor axially. Both the tongue and groove are undercut so that resistance draws the extractor claw inward to prevent slipping off a stuck case ...

"As noted previously, the M98 bolt face and extractor create a feed sequence safeguarding against double-loading. To assure this is not defeated by by-passing the magazine, the M98 is set up to discourage any habit of feeding cartridges directly. The face of the already-stiff extractor hook is angled to prevent it easily closing on a chambered round.

"About 1/32 in. extra clearance is broached into the right raceway at the receiver ring, however, in this and other actions with the external Mauser extractor, and even though the M98 extractor will not cam itself over a case rim, this can be accomplished externally by squeezing its side as the bolt is closed. Without this technique, the Mauser can be easily jammed in the field, particularly when converted for cartridges which do not smoothly feed from the magazine."

So, Paul Mauser made allowance for a pushfeed, should the magazine be jammed full.

That tongue and groove/dovetail is a marvelous little detail. Traction backward against resistance pulls the extractor inward toward the center of the bore axis, and grips the cartridge securely. Pushing the bolt forward against the pushfed chambered cartridge and pushing on the side of the extractor, allows the extractor to cam over the cartridge rim, even in the battle rifle, Mauser 98.

As Rick points out the M70 Winchester, Ruger M77, and most of the commercial Mauser clones [except some such as the BRNO ZKK 602 possibly (and I think the "half-dovetail" Martin describes is the same as the original M98, the groove is undercut/sloped in the forward/muzzleward face, while the rearward face of the tongue and groove are perpendicular to the long axis of the bolt)], are set up to easily pushfeed.

The clones are designed to do this, but it probably does mean that they might be more likely to fail with a badly stuck case in the chamber, such as with over-pressure.

This is not too comforting, except to the Pure M98 or 602-type-clone owner. I never looked at this bolt head detail on the FN, Whitworth, Brno ZKK 602, CZ 550 Magnum, Ruger Mark II, BBK-02 actions that I have, let alone the Oberndorf and high end stuff.

Get out the magnifying glass and the spotlight!

Better reason than ever to avoid hot loads, grimey chambers, and bad brass in the CRF rifles, whether they PF or not. Or any rifle at all, pure PF, pure CRF, or CRF+PF modified.

I wouldn't try to modify the real deal M98 or the 602. The others being able to PF is O.K. by me, though you will find me treating all the CRF's as CRF only, unless the magazine is jammed full and the only option is making the extractor snap over the rim to save my bacon. Oink oink.

------------------
RAB

[This message has been edited by DaggaRon (edited 04-19-2002).]

Will,
Thanks for the copy of your story about the elephant hunt. My copy of AH is on the slow boat from Zimbabwe, or wherever.

You were right to be confused, as the way I presented this initially, it appears I was confused by the newly acquired 458. My CZ 458 did not pushfeed easily, so I did not force it, thinking I had some variant. Just a little polishing of the forward lower edge of the extractor allowed it to cam over easily in push feeding.

If the old BRNO ZKK 602 is like the M98 in this regard, I may just have to leave it alone. That was a fine factory gun except for the bassackward safety and funny trigger it used to have, and of course those old 602's didn't have the polished finish of the CZ 550's.

Now I gotta go read Will's story and finish the reloading for the weekend shooting.

------------------
RAB

[This message has been edited by DaggaRon (edited 04-19-2002).]

Daggaron:good and clear post.

I did not know about the squeeze trick,like I stated I don't have 98 handy and I always thought the Mausers had a dual or full dovetail and if so this would not allow the extractor to move at all now it seems they have a simular set up as the 602's.

ps any idea's on the replacement extractor for the M70 Wich.

Regards Martin

Martin,
I am on the same page as you are.

I do believe PME (Precise Metalsmithing Enterprises, Inc.), James & Jennifer Wisner, make the spring steel replacement extractors for the Winchester M70.

My old catalog of theirs showed these, and contact info:

P.M. Enterprises, Inc.
146 Curtis Hill Road
Chehalis, Washington 98532

(360) 748-3743

I would have to verify any of this information as current, but that is what I have at hand ...

Done. See next post for more info and web links.

------------------
RAB

[This message has been edited by DaggaRon (edited 04-20-2002).]