M14 Forum

casebro

Not like from Thor, but a lighter hammer strikes faster. Faster lock time = better accuracy. Less time to wander off-target.

My XP-100 got an aftermarket Titanium striker just for that reason.

Anybody ever try it on our beloveds?

82nd ABN

Not sure if anyone makes them. Do you have a source? I think I saw a trigger that was relieved of some material do make it lighter but theta about it. Personally aside from a trigger job I have not tried a lighter hammer.

Ted Brown

Among other benefits the M14 hammer is designed to strike with enough force to fire less sensitive military primers. The hammer system is designed so it actually accelerates faster as it moves forward. .0056 to .0058 seconds is pretty fast. The M14 is not a bench rest rifle so I don't know that faster lock time is needed although I'm sure some may find it desireable.

casebro

Ted, there certainly would be a limit of toooo light.

I was wondering if anybody had tried it.

Best way to tinker would be to drill a hole through the center of mass. Higher the better. May take a carbide drill though.

So far as energy stored in a hammer, waiting to hit the pin, half as light moving twice as fast, would have just as much energy. Or maybe twice as much? Physics, any one? .003 would be better than ..0058, eh?

And like so much accurizing, it's all marginal. But the sum of the accurizing is worth the work.

I have two Winchester shotguns. My Model 25 (a M12 that doesn't break down) has a hammer/spring system similar the the M-series GI. My Model 50 uses a hammer about 1/3 the weight, with a rat-trap type coil spring. The M14 type starts off very slow, has maximum push against the hammer right at the pin,because of it's geometry. The other gun with that wimpy little wound rat-trap spring has it's maximum power while hammer is against the sear. Good initial speed that way. I swear that light hammer system takes only 1/3 of the lock time. I didn't invent this, I noticed the huge difference when swapping from gun to gun on the trap range. Faster lock time there = less leed needed. Striker fired guns are faster yet, like hammer less doubles and most bolt guns. Hammer weight vs power? How much does a striker in an '03 weigh? They both hit the same primers.

nately

Correct me if I'm wrong, but the total amount of energy transfered to the primer should be the same no matter how heavy or light the hammer because the amount of energy the spring can deliver each trigger pull is fixed. So perhaps light primer strikes wouldnt be a problem?

Is the hammer on the Garand the same as the M14? Same enough that a Garand drawing would suffice for an M14 replacement part? Im already drooling over a titanium hammer.

FWhite

Ever see the drawing for a M14 hammer? Not the sort of thing to undertake at home. The cam surface that the bolt engages takes almost a whole sheet to describe.

2336USMC

There was a modified M14 hammer on GB for quite a while. guy went after it on a mill, the whole back side of the hammer was milled out down to a skeleton outline. It didn't look very strong to me, like you could expect it to stress crack and break shortly.

That may have been too much but I guess the point is it has been tried.

bd111

Some guys used to drill holes in hammers to make them lighter. There are some photos here on the board somewhere that show a hammer that was hollowed out on the safety side. Good idea, bad idea, I can't judge. I do think the Tubb hammer spring may be a SLIGHT difference maker in drop time. But I've never weighed it against a standard GI spring.

nately

I could imagine. The more I study the drawings, the more impressed I am with the design of the M14.

would you happen to have a copy of the trigger assembly drawings?

FWhite

I have drawings for the trigger, hammer, trigger housing and trigger guard. No assembly drawings.

art7

I've done some hammer design work, so I studied up on this.

Total energy in the system is dictated by the amount of potential energy stored in the hammer spring. The difference in energy between the cocked state and the relaxed state is the amount of energy imparted to the hammer in the form of 1/2*I*omega^2, where I is the roational momnt of the hammer (analagous to mass in a translational system), and omega is the rotational velocity. Lightening the hammer will reduce I, and thus will increase the hammer velocity, reducing lock time.

However, you also have to consider the mass balance between the hammer and the firing pin to determine the efficay of energy transfer. If you hit a billiard ball with another, so the mass is the same, 100% of the energy will transfer (assume a straight impact). The cue ball stops, and the impacted ball gets all the energy. If you hit a ping-pong ball with a billiard ball, only some of the energy will transfer, as the billiard ball will continue rolling forward after the impact, and so will retain some of its original energy. If you hit a bowling ball with a billiard ball, it will only transfer some of the energy, as the billiard ball will rebound, retaining energy in the opposite vector. So, to get ideal energy transfer, the I of the hammer should be matched with the mass of the firing pin. I have not run the math on an M-14, but can say that if you just lighten it, you might get less energy transfer.

Unfortunately, you can't just put in a heavier spring, because the hammer sspring doubles as the trigger spring, so your trigger pull would go up.

Art

82nd ABN

Still trying to figure out how faster lock time equates to better accuracy. As it is with my rack grade the bolt has already chambered a round long before I recover from the recoil. Isn't it fast enough already? Sort of a mute point.
I can see if you wanted to increase the cyclic rate it might be worth taking a shot at but thats going to involve a lot more than just making the hammer lighter, don't ya think?

casebro

82nd, everybody wiggles when they shoot.

The way I was taught to shoot is to take aim, and tighten on the trigger. As you wander away from proper sight alignment, hold that pressure until you get back on target. Then tighten some more. The gun actually goes off as the sights pass across the target. (didn't they teach you that?) So, faster lock time = less wander away from the target. Big help in off hand, I would think.

And to answer another question, Yes M1 and M14 shared much of the trigger group, including hammers, at least in semi-auto versions. I think the ears on the sear are the biggest diff, that's where the selector parts trip the sear.

I've got one spare, a brand new Springfield Arsenal. My M14 has a TRW. I don't know which to experiment on.

But while nearly on the subject, what is the hardest primer? GI M80?

82nd ABN

Yes but like I mentioned the cycle has already taken place by the time I a have recovered from the reciol. So if the action cycles faster than anyone can get back on target what's the point of having a faster hammer if it's already faster than you can point aim and shoot? I'll say it again yes I can see the benefit in full auto mode but to increase the cyic time many other changes will have to be made long before the hammer regardless of what I wast tought!

Old Sarge

Faster lock time can improve accuracy. The lock time on the old '03 Springfield rifle with its big, heavy striker rod was rather slow, and Springfield Armory had some modified NM rifles with faster lock times. Often times though, the ignition was more erratic and sometimes had pierced primers.

I'm not trying to dispute or argue what Ted Brown stated. Just merely adding my thoughts to it.

I know a guy that has an M1A and his accuracy went sour on him and he couldn't figure out why, so he sent his rifle back to SA Inc. for a checkup and they found a weak hammer spring. That little $5 spring was causing weak, erratic ignition and loss of accuracy.

My assumption would be that by going to a lighter hammer would necessitate a heavier hammer spring, but then as someone stated in a post above, resulting in a much heavier trigger pull.