So what is the opinion on the Dayton Traister cock on open kits for the mexican mausers? Good or bad?

If you don't like COC, I don't, the D-T kit is your only option if you want COO. The D-T kit isn't drop-in and those that I've installed have all needed extra attention.

My small ring Mexican 98s are COO.

I’ve switched over a 1917 to cock on open. I wouldn’t do it again.

I can't answer your question. That said, a more fundamental ones. Simplicity, strength and ergonomics. With emphasis on the latter. As... Why convert? I've had a few '17 Enfield conversions and IF as them, including a "speed striker", by whatever name/term, a quite heavy bolt lift. Yet beyond such 'complications', yet the strategic "Why?" The pasue IF speaking of "bench or prone shooting", simply ignore all of the following. Such positioning where reaching over the bolt from normally passive hand" another case entirely with opposite conclusions. Otherwise, moving right on...

My belief an 'aura' created by the dominance of Springfield '03 and Mauser 98 actions "cock on opening" inherent style. Yet such as P14 & P17 Endfields and their wider Brit gender, not just "sub" said Springfield/Mauser variants not achieving the "cock on opening" pinnacle!

To strip the generations old hype for cock on opening, more fundamentally, what's exactly wrong with "cock on closing". More "aura" than fact! Factually the "cock on opening", as spring tension-loading of striker via torsional force resistance; aka twisting of the rifle and 'of which' the forearm wrist necessarily "resists" that torsion to achieve striker "cocking". Conversely, :cock on closing" presents a linear force moving away from the shoulder to be resisted by holding the rifle quite in the same manner as shooting, resisting the same forces. Striker spring force overcome as 'resisting' rifle moving away from the shoulder. Here, exactly the same resistance as shooting stance accuracy-impairing. Rotational forces introducing a secondary movement direction to be resisted!

But more! The cock on closing requires minimal force for extracting & clearing the spend round from the rifle. Such movement unimpeded by 'other force' duality of overcoming spring resisting cocking. Only in the final moments perhaps 15% or so of bolt achieving battery, does "cocking on closing" striker spring resistance occur. The cock on closing bolt as simpler; not requiring the hardened precision-angled cocking cam notched in the aft bolt body as "cock on opening" mandates.

The 'net' to me, a more natural and less fatiguing "cock on closing" force to overcome. For "senior folks", the considerably less stressful avoidance of rotator cuff forces as itself requiring twisting of vulnerable human skeletal structures in both arms. The bolt to be twisted open and the other arm resisting such torsional movement. The entire large arm (stronger) muscle set employed with "cock on closing" 'linear' system as alternative to 'torsional factors' required of shoulder joint participation.

I personally find it more comfortable and less fatiguing in string-fire rapid follow up shot situations where the rifle preferably not lowered to such as perhaps forty five degrees before ejecting the spent shell. In that forty five degree 'down bubble' the entire of the bolt mass may also be employed to assist in "cock on closing" effort. The typically 'counter-clockwise "cock on opening" without such benefit as potentially clumsy.

The cock on closing action engineering tending to be a 'bit' potentially stronger, as simpler and more rugged achievable design than the cock on opening. On quality bolt rifles, making perhaps 'no difference' per se. Yet in either the "Mud of Flanders" or in your own shooting field, perhaps the "cock on closing" edge offering that small advantage!

Just my take as begging pardon for any redundancy, etc., as composed & submitted without edit!

Best!
John

Cock on closing was the brilliant invention of some lost to time inventor.

It reduces the amount of effort on primary extraction to 1/2 that of cock on opening.

Perhaps most famous in the SMLE where the WW I Germans thought every Tommy had a machine gun.

As much as everyone loves the Mauser, the SMLE was a far superior battle rifle.

COO conversions are far too often a mess as well as unnecessary.

The most brilliant "modern" bolt action, Schultz & Larsen also split the effort because they knew a COO with a 45 degree bolt lift was a bad idea. Also like the SMLE they have rear locking lugs that shorten the bolt throw.

We know what action Roy picked for the first 378 BEEs, don't we ? Slicker than greased kitty litter !

My custom Swede 7x57 that Jim Wisner put together uses the LaPour CCO conversion and three position safety. This kit (along with many others) is in re-development by Nathan Myers.

https://www.myersarms.com/store/Ed-LaPour-*PRESALE*-Mauser-1896-3-Position-Safety-Bolt-Shroud-p435881063

That's a beauty.

I've seen some issues with the cock on open conversions.

I agree John. I have examples of both right now. The one COO that I keep around works wonderfully though. Much like a good model 70. It's my sporter m1917:


It had some issues when I got it, as the original owner installed the COO kit, but left the original military trigger. I ended up buying a Timney sportsman trigger and installing it. Having to fine tune it to get it to function properly. Works very well now though. I was leery about the COO though because I've seen a few with issues. Ran into some at gunshops or gunshows that would fire on their own. Having grown up with the m1917, I know my way around them pretty well though and got mine to working 100%. The one I grew up with was COC, which you get used to after a while. My BSA model E is still COC and I am not going to mess with it. It's not worth doing the conversion on it. The COC is more robust and dependable from what I've seen, so why mess with it:


We've all heard that the COC models were faster to manipulate, so maybe a better wartime choice. For a modern sporting rifle I don't think it matters much. With this being said, I would not convert a good rifle with COC to COO..

I have had several guys tell me that they get used to cock on closing type military actions, and dont really notice it after awhile.

The reason i asked is I have a mauser that i had a member here "Jkob" install a swing safety on, I really the gun but honestly when you push it forward to cock it , its a flat out B-TCH to close.

I looked at my records and see that the most that I ever paid for a pre-1898 military Mauser to rework was $230, so I'd be hard pressed to justify paying $405 for an Ed LaPour 3-position safety bolt shroud for one of them. That said, I have a mill, a lathe, some trial and error skill, and plenty of time to do the metal work, so installing a D-T COO kit is just something to do when I'm not doing something else.

If you like COC, leave your rifle as it is. If you don't, the D-T COO kit isn't very expensive to buy, but if you have to pay someone to install it, it might not be worth the cost.

I don't like COC and the guy who I have reworked most of those pre-1898 military Mausers for doesn't like COC either, so when I rework those rifles for him and for myself, I always install a D-T COO kit.

So $230 for the COO conversion and three position safety parts? Good deal for sure.

Where COC often catches people out is when they are at the range, taking their time, babying the rifle. When you run it like there are a platoon of enemy closing on your position, or when you have a chance at a quick follow up on a mob of pigs, you'll soon forget that it is COC. Doing a bit of dry practice, slamming that bolt back and forth like you want to wrench the bolt knob off, may also help here.

One other thought too: there seems a common practice in the US of "palming" the bolt. Here and in Europe people grasp the bolt knob between a curled forefinger and the thumb, which IMHO gives you rather more control.

Of course, another possibility is that someone installed a stiffer mainspring...

Dan has it right.

I'll always remember the old Sgt telling us boys (with 03s) "Run that rifle like you're trying to rip that bolt out and slam it home like you're trying to break the bolt handle off !"

You do that and COC is no issue.

(don't do it on a 700, the handle might come off.)

The problem with some conversations is the required grinding angle on the bolt body can be steep enough to cause enough extra effort that a fellow might wish he didn’t mess with it.

No, I paid between $110 and $230 for each of 22 Swedish Mausers, the raw materials you might say. The D-T kits were around $40 each from Brownell's the last time that I bought one of them. Plus the commercial style bolt shrouds, the Bold or Timney triggers, the stocks, etc. The only rifles that I have with 3-position wing safeties are Winchester 70s. I don't like them enough to spend the money for the parts, the grinding fixture, or a complete finished unit for a mil-surp build.

There is not a damn thing in the world wrong with COC. If you (the generic you) can't deal with a time proven, battle proven system designed to be operated by the dumbest peasants around the world, you probably have trouble with a manual can opener and cringe at the thought of driving a stick shift. As a helpful suggestion...have you looked into semi auto rifles?

(And all of my vehicles are stick shifts - and will remain so, 21st century be dammed!)

"The Americans built a target rifle (1903 Springfield), the Germans built a sporting rifle (98 Mauser), but the British built a fighting rifle (SMLE)."

While COC was of value in a bolt action military rifle designed prior to the introduction and adoption of gas operated semi-automatic military rifles, that era has long passed. For hunting applications, I don't see any added value of COC and if there was some, surely someone would have designed a new bolt action to take advantage of that benefit. No doubt the Enfield was a better combat rifle than the Springfield, with its larger magazine capacity and being easier/faster to cycle. If your "mob of pigs" scenario occurred in the U.S., a person expecting such an encounter would likely equip himself/herself with a semi-automatic firearm that featured a large capacity detachable magazine rather than with a manually operated firearm.

The logical thing to do is keep both on hand. The 17" bayonet on the front of a SMLE might be useful if conditions deteriorate enough or if those pigs keep coming. The 10 round SMLE must have been something going against a 5 round mauser.

Have an 1895 Chilean with COC, I really like it

How do you adjust windage/elevation with that setup? That looks like a B&L Balvar scope but I don’t see the adjustable bases that are normally used.

I have a DT kit sitting here for about 20 years. I never installed it on the Scout Swed. :-)

The Schultz & Larsen are so straight you don't need any adjustment :-)

Do they make a COO kit for Arisaka rifles?

A moot point, considering that most casualties occurred via machine gun, disease, and artillery.

"How do you adjust windage/elevation with that setup? That looks like a B&L Balvar scope but I don’t see the adjustable bases that are normally used."

The one shortcoming of the M 54 S&L is that it was designed before huge turret scopes. When one is used the empty hits the turret and may fall back in the action.

The BalVar 8 removes that chance and is a fine optic even today. That one is a rare one with tapered CH and a small dot.

The Mounts are S&K which have opposing screws on each base so windage is easy.

Initially it was about 10" high, so a small shim under the rear base brought it to 3" high as JOC suggested.

You do have to pick a load and stick with it.

Aussies are killing their pigs with machine guns, disease, and artillery?

I happened to have been considering the difference in fire power between the SMLE and the German Mauser, and in a broader sense their handling characteristics when under duress. Funny I've never heard anyone else say that the 10 round magazine of SMLE was a moot point. I'll bet the Germans were wondering when those British rifles were ever going to run out of ammunition.

When the M98 was designed for COO, the rear of the bolt body was thicken to provide a wide spiral cut cocking ramp to lessen the risk of galling and premature cocking ramp wear. Something to consider when converting a COC bolt to COO.

See pg 100 of Jerry Kuhnhausen's The Mauser Bolt Actions, a shop manual for more technical/mechanical details on why he does not recommend the conversion.

I do have a Pattern '07 bayonet for my SMLE (a bayonet whose design was lifted wholesale from that of the Arisaka of 1905). With a good team of dogs the bayonet can be used quite effectively to kill wild pigs, even without the rifle, or so I've found.

I prefer coc, wasn’t a huge fan of it in my first rifle (7.7-06 Arisaka), but I’ve come around. I’ve owned 7 coc rifles (3 arisakas, 2 2A1, 1 1917, 1 1891 Mauser) and 12 coo rifles (2 98 style, 1 88/05/35, 1 Mosin, 6 carcanos, 2 vetterlis) that I can recall, and that’s not even getting into the various 22’s I can’t remember. The vetterlis get a pass because they’re stupidly smooth, but 90% of the time I’d rather have a coc because I regularly smack that bolt home hard, and the transition the spring provides feels nicer than the abrupt stop of a coo action.

I have a 1893 Spanish Ovideo mauser 7x57 and a 1917 Eddystone 30-06 both coc. Not gonna fix what isn't broke they are fine the way they are....mb

I'm admittedly COC prejudiced (Duh - Ya think! :)) Yet most of my bolts are COO since particularly in sporting context, such the way of the world in respect of my primary interests through the seventies era and again in the nineties in context of the FN production era of Winchester Classic CRF line. The COO or COC really does come down to personal preference/prejudice.

A short side note concerning the Schultz & Larsen rifle mentioned above. A Danish firm making high quality rifles as unable to achieve the production numbers to be competitive in the American market as principally targeted in the fifties under Phil Sharpe as importer or the sixties under the mighty Norma Precision Firm backing. The S&L, An expensive rifle of aft lug locking design and even to date perhaps moved from largely "unknown" to largely "past era exotic". The first models of the fifties were COC, a transitional model and wrapping with two COO models in sixties era.

With the milsurp market of the American fifties, the COC action was established as 'almost exclusively' associated with military design and surplus context. The interwar Remington Model 30 earlier years were the proliferant COC design featuring the civilianized Model 17 Enfield action. To my tastes, great rifles. The S&L were exotically partially hand-crafted, of great quality of materials and workmanship. I congratulate anyone owning one! I have five, all acquired as "also ran unknowns" and such prices reflected!

Thanks those of you who put up with another dissertation!
Best!
John

fine minds think alike, I've owned a 1917 and a SMLE along with other COO rifles and never was bothered.

Balvar 8 in windage adjustable mounts, slight shim for elevation, 22-250 and dotes on 52gr Speers

Good points John. However, I don't know if it is exactly "personal preference". My actual preference is to the newer rifles with COO. But when it comes to my favorite m1917, I'd rather people just leave them alone and leave the COC feature. Sure, change the crappy trigger to a Timney sportsman, like I've done a dozen times. That is a necessity, not just personal preference there, but a damn necessity!!!!! Now, I grew up with a COC sporter m1917 and I got used to it. They work great, but do I prefer it over a Winchester model 70 pre 64 or Classic? Not hardly. My m1917 with COO works perfectly and it feeds better than any Model 70 I have in the safe. There's beauty in that for sure. My BSA model E 308 Norma also feeds well, but it retains the original COC feature. It works great. Guys that have never had one, can't appreciate it..

My first rifle was a 1895 Chilean, I got used to the cock on close, I'm good either way!

Why did Mauser change?

Bruce