Home Forums Hunting & Shooting Mausers and Military Rifles Opinions- Cock on open conversions

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.