Adjusting trigger timing, firing pin fall, Rem 700?

J

Jay Idaho

Guest
I'm setting up a couple of Rem 700 bolts, Savage bolt head conversions, and have some questions. These will be for 6-6.5X47L, SR primers.
The new bolt head moves the dryfire stop rearward during the conversion so you must take material from the front of the firing pin shoulder. This also requires turning the firing pin diameter down and shortening the tip.
This is a perfect time to fine tune firing pin protrusion, firing pin travel and "handoff" of cocking piece sear to the trigger. You can slightly increase the firing pin travel or reduce it as much as you wish at this time. This does require machining of the rear of the bolt body but that was discussed recently on another thread.
1. What is the optimum firing pin fall? (Less should make cocking slightly easier, I think)
2. What is ideal firing pin protrusion?
3. Would you bush the firing pin hole to be a close fit to a .060 firing pin diameter at this time?

Thanks for an input,

Jay, Idaho
 
Jay

I have Farleys, which are pretty close to a Remington.

I played with the trigger hangers untill I got the fall at no less than ,220. (not easy on a Farley). I also set the spring tension at 22-23 lbs.

As far as the tip protrusion, I would feel free in saying that .045-.050 is ideal.

As for the .060, you do not have to go that small. My Farleys have a .068, and they handle anything I feed them, which, as you might know, is up there.

The Stiller Diamomd Back that I built my 30BR LV-Sporter on does feature a .o625 firing pin, it seems to work just fine, as the Rifle shoots really well.
 
I had to move the firing pin's cross pin forward. Otherwise it had something like .190 total firing pin travel. The Vipers have about .200 firing pin drop. I think my 40x ended up with about .210.
 
crb said:
I had to move the firing pin's cross pin forward. Otherwise it had something like .190 total firing pin travel. The Vipers have about .200 firing pin drop. I think my 40x ended up with about .210.
Click to expand...

My early Viper came with .200 with a HVR Jewell. Sometime after I got it, Jerry told me that he feels that there is no substitute for enough pin fall, and that he recommended turning the trigger hanger around to gain some. I did that, and after had filing a matching clearance not in the other end, I ended up with .220. The hand off had been perfect, so I ended up with .020 cock on close, which is totally unnoticeable when the bolt is operated at the speed that I normally do. Although I did not notice any difference, I left it that way. The action came with a crudely cut off striker spring that measures #19 cocked. Since then I have played with a number of combinations of springs, the stock pin, and an aluminum shafted one. None has shown any definite difference, except the light pin shows less reticle movement from dry firing on an empty chamber. Perhaps the small firing pin tip has something to do with that. I think that they require less energy to function properly.
 
Jay,

Somewheres here in BR Central cyber space, there is an outstanding post by Jim Kelbly wherein he discusses all things ignition concerning the 700, and why Mike Walker designed it the way he did based on his testing. I tried to find it and post a link, but was UTL...

See if you can find it. It is well worth the read.

Justin
 
How far

crb said:
I had to move the firing pin's cross pin forward. Otherwise it had something like .190 total firing pin travel. The Vipers have about .200 firing pin drop. I think my 40x ended up with about .210.
Click to expand...

does one move the new cross pin hole if one wants say .050" more fall is it a simple .050" move forward?

Thanks,

Pete
 
It is not that simple. You need to maintain a little gap in the dry fired position of the pin, between the front of the cocking piece and the bottom of the cocking cam notch. Since the existing gap is less than .050, moving the hole as you mentioned would result in the pin fall being reduced by the difference between the existing gap and .050, and the cocking piece acting as the dry fire stop instead the front of the firing pin flange. This is not desirable. Ultimately the working depth of the cam notch, plus the amount of cock on close add up to the pin fall. You can cheat this some, but not that much. You may note that Jackie mentioned using as little as .040 protrusion. The difference between that and what you currently have would be added to the WORKING fall ( as opposed to the total fall). When firing a live round, the primer stops the pin, not the front of the flange. If you think about it, as you increase the protrusion, the WORKING fall is decreased.

If you assume that Jackie knows his stuff and that a minimum of .040 protrusion does not hurt accuracy, and you have say .055, shortening the tip by the difference would increase the WORKING fall by .015. Just looking at total fall can be deceiving since the primer acting as a stop during firing does not let the pin fall to that extent.
 
We have found in testing military ammo in a Universal Receiver, that we need to have .030"-.039" firing pin protrusion and .020"-.025" firing pin indent in a SAAMI copper for 5.56mm small primer, and .060"-.068" protrusion and .020"-.025" indent for 7.62mm large primer, both being harder military primers, for reliable ignition in all conditions.
 
Not sure if they are still around, but Stan Ware made some excellent videos on Remington trigger timing, bolt lapping, etc...
They were on his website initially, but I belive it is no longer functioning.
Mike
 
Stan dropped out

savet06 said:
Not sure if they are still around, but Stan Ware made some excellent videos on Remington trigger timing, bolt lapping, etc...
They were on his website initially, but I belive it is no longer functioning.
Mike
Click to expand...

Don't know why. He HAS some Youtubes on the bolt timing that were very well done and relocating the bolt handle for extraction. SGR.

Pete
 
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I've been getting

MilGunsmith said:
We have found in testing military ammo in a Universal Receiver, that we need to have .030"-.039" firing pin protrusion and .020"-.025" firing pin indent in a SAAMI copper for 5.56mm small primer, and .060"-.068" protrusion and .020"-.025" indent for 7.62mm large primer, both being harder military primers, for reliable ignition in all conditions.
Click to expand...

not all that much indentation in my SR primers with .055" pin tip protrusion, actually had to increase it by .005" to get them to fire in that rifle. I'm quite sure 30 to 40 thou wouldn't do it in the rifle. Not saying it won't in others but dealing with what I have. I'm going to use one of the pins I have to drill another hole in it, shorten the butt and the front of the cocking piece and see what happens. Ill report what I find. As an aside, the .220" both rifles have for fall seems to work but one always wonders if they might find more, doesn't one?

Pete
 
Pete Wass said:
not all that much indentation in my SR primers with .055" pin tip protrusion, actually had to increase it by .005" to get them to fire in that rifle. I'm quite sure 30 to 40 thou wouldn't do it in the rifle. Not saying it won't in others but dealing with what I have. I'm going to use one of the pins I have to drill another hole in it, shorten the butt and the front of the cocking piece and see what happens. Ill report what I find. As an aside, the .220" both rifles have for fall seems to work but one always wonders if they might find more, doesn't one?

Pete
Click to expand...

Before you do that remember that doing so will position your cocking piece farther forward relative to the front of the firing pin flange. Check how much clearance you have between the bottom of the cocking cam notch and the nose of the cocking piece. If you move the hole forward by that much or more, your cocking piece will become the dry fire stop and the cross pin that secures it will take all the impact. Not good. Of course this will probably only be when you are dry firing, but still it is not a good idea. Normally, when actually firing a round, the primer stops the firing pin, well short of maximum protrusion. If I were you, I would be doing a lot of measuring to see why you need that much protrusion to fire a primer. Something unusual is going on there. How deep are your seated primers below your case heads?
 
I have not measured the primers

Boyd Allen said:
Before you do that remember that doing so will position your cocking piece farther forward relative to the front of the firing pin flange. Check how much clearance you have between the bottom of the cocking cam notch and the nose of the cocking piece. If you move the hole forward by that much or more, your cocking piece will become the dry fire stop and the cross pin that secures it will take all the impact. Not good. Of course this will probably only be when you are dry firing, but still it is not a good idea. Normally, when actually firing a round, the primer stops the firing pin, well short of maximum protrusion. If I were you, I would be doing a lot of measuring to see why you need that much protrusion to fire a primer. Something unusual is going on there. How deep are your seated primers below your case heads?
Click to expand...

but they have been trued up with a standard SR uniformer I have been using for the 20 or so years I've been benchrest shooting, it not ever have been a problem in any of the other dozen or so BR rifles I have owned and shot over that time. Actually, the problem manifested itself before I "Uniformed" the pockets in these cases. I took Al's advice on shooting them first before unforming. Likely the .220" fall is adequate as the Sister action or Brother depending if a Bolt Gun is male or female has always shot very well. I simply wanted to go with what the Father of the 700 recommended is all. Any additional modifications necessary I can do. There is a difference in the age of the actions, the newer one being one of the latest SS 700s available for sale at selected stocking dealers. Doubt if that makes a difference but who knows? The extra .005" didn't unduly indent the primers.

Pete
 
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