Bolt timing

Pete Wass

Pete Wass

Well-known member
I have a couple of BR rifles that when closing the bolt on them, I have to push the bolt slightly forward and I can feel the lugs hook the action on closing. I asume the trigger is positioned too far rearward but don't know for sure. Is there anyone out there who specializes in timing actions to be easy to close and easy to open? I once owned a rifle that had a bolt which seemed to have a bit of spring assist when it opened. I must say, I liked that.
 
One of them

has a bolt handle that can not be removed. The other is a popular brand which has a soldered handle on it. It would be nice if there was some way to make the adjustments without major machining or modifications, wouldn't it? I have watched Stan's video several times. It was my impression that he was more concerned about extraction than the actual timing although they go sort of hand in hand to some extent.

DAAH! I just went to the link you sent and read the post Al N put there. Nicely done and now I have a decisoin to make!
 
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Isn´t it just a matter of changing the trigger hanger?

The bolt handle shouldn´t have anything to do with the issue.
 
For me, resistance during closing of the bolt has always been due to wrong trigger hanger. Dificult opening of the bolt has been a matter of bolt handle in the wrong place.

But, I might be wrong in this case:)
 
If your action has an ejector, you could be hanging up on the ejector pin if it's a little too long. The ejector shouldn't protrude farther forward than the end of the bolt nose. If it does, then it needs to be shortened and radiused off a little after shortening.

You should be able to lift the bolt handle straight up and close it straight down and have the bolt cock. If you have to pull the bolt to the rear slightly and then close the bolt, then the bolt is cocking on closing somewhat and could use the trigger positioned forward a little. Also, if the firing pin drops a little when you close it, then the trigger needs to be positioned more to the rear. The ideal would be to be able to raise the bolt straight up and close it straight down, cocking the firing pin back without allowing firing pin to drop forward when the bolt closes.
 
Thanks Mike

Mike Bryant said:
If your action has an ejector, you could be hanging up on the ejector pin if it's a little too long. The ejector shouldn't protrude farther forward than the end of the bolt nose. If it does, then it needs to be shortened and radiused off a little after shortening.

You should be able to lift the bolt handle straight up and close it straight down and have the bolt cock. If you have to pull the bolt to the rear slightly and then close the bolt, then the bolt is cocking on closing somewhat and could use the trigger positioned forward a little. Also, if the firing pin drops a little when you close it, then the trigger needs to be positioned more to the rear. The ideal would be to be able to raise the bolt straight up and close it straight down, cocking the firing pin back without allowing firing pin to drop forward when the bolt closes.
Click to expand...

It has been a few days since I have looked here. I will check them out as you have outlined. A common thread among them seems to be the distance between the extraction cam and bolt handle. Several of them appear to be too far away to provide good caming.
I think I did discover the ejector pin as being a problem in the interum and I will rectify them. Should the pin be slightly below the rim around the face of the bolt?
 
Pete, don't confuse mechanical camming (primary extraction) with how the trigger picks up the cocking piece. Both fall under the 'bolt timing' umbrella, but there's more to it than that. Mike Bryant has given some great advice.

Most action mfgs. sell hangers with repositioned pin holes or will sell you a blank hanger w/o holes. I believe that Kelbly's sells them in .020 increments for their actions.

My 2 cents worth. -Al
 
Bolt timing unbrella

The Bolt Timing issue is indeed an unbrella as Al Nyus has mentioned.
There is easily a dozen functions envolved. Some of these functions
overlap , So its important to study closely before making permanent
changes. This is not rocket science, but much of it is not obvious
untill its to late.
 
Pete Wass said:
It has been a few days since I have looked here. I will check them out as you have outlined. A common thread among them seems to be the distance between the extraction cam and bolt handle. Several of them appear to be too far away to provide good caming.
I think I did discover the ejector pin as being a problem in the interum and I will rectify them. Should the pin be slightly below the rim around the face of the bolt?
Click to expand...

The ejector pin needs to be short enough that it doesn't hang up on a case head when you push the case in with the bolt. Generally, the longer the ejector pin the better it will eject, but if it's too long it will hang up on the case. When you push the bolt forward with a loaded cartridge, if it seems to hang and then you have to pull the bolt back slightly and then push forward again, there's a problem with the ejector being too long. This is something that shooters tend to get used to doing even to the point that they don't notice it. Where you'll really notice it is when you go from a benchrest rifle which is feeding correctly and the ejector pin is working properly to one where the cartridge is hanging up on the ejector pin. You'll notice it very quickly then.

As to extraction bolt timing, the closer the bolt handle is to the front of the bolt handle cutout the better the extraction will be. How close you can get the bolt handle depends upon how close the cams in the front of the receiver match the cam in the rear of the receiver. The cams in the front of the receiver are the closing cams. The cam in the rear of the receiver is the extraction cam. The cams don't have to be the same. The closing cam can have more camming than the extraction cam and still be able get all the extraction cam that the design of the action is capable of having. I personally like the bolt to move at least 1/16" and more would be preferable, to the rear from full closed to full up on the bolt handle.

Lack of extraction camming happens quite often with trued Remingtons. Some of them have marginal extraction camming before the action is trued. Then when a few thousandths are taken off the receiver lugs and the bolt lugs, the extraction camming can go from marginal to not much. The remedy is to remove the bolt handle and move it forward as close to the front edge of the bolt handle cut out in the receiver as you can get it and reattach it to the bolt body.
 
The ejector pin

situation you discribed is exactly the situation I have. I will look this aftrnoon.

I understand what the cams all do. I haven't measured it yet but I am guessing the gap between the bolt handle and the caming surface is 1,8 to 3/16. I think it is too much. Seems to me it ought to be a few thou instead of fractions of an inch. Anyway, the thing works but I feel it could be better, after all, it is a Custom action.
 
Pete, I have a Nesika J action that always been one of my best shooting rifles. It has the bolt handle integral with the bolt body. The bolt handle has .011" clearance between the front of the bolt handle and the rear of the bolt handle cutout on the receiver. The bolt moves .090" to .092" to the rear from fully closed to the bolt handle raised straight up. This is measuring from the rear of the bolt handle to the rear of the receiver cut out from before it starts camming out to when it's all the way raised. My Panda has about the same clearance in front of the bolt handle and it moves .082" to .084" from closed to straight up. A Farley that I have has .005" clearance between the bolt handle and bolt cut out and it moves about .100" from closed to straight up. A Bat DS I have has .007" clearance and it moves about a .100" as well. Those 4 different actions should give you an idea of what the dimensions should run as they are all pretty close on the amount of extraction camming. If your dimensions are much lower than in that range, then you might have a problem with extraction camming.

The distance that the bolt moves back to me is more important than how much clearance is in front of the bolt handle to bolt cut out. As how well the cam on the bolt handle works with the cam on the receiver is more of an indication of how well the extractor camming is working than how much clearance their is between the bolt handle and the front of the bolt handle cutout in the receiver. The bolt handle could have just enough clearance to close in the receiver and the camming would do nothing as to moving the bolt rearward, if the matching angles on the bolt handle and receiver weren't fitted right.
 
I checked

the ejector pins of three rifles and here is what I found:

1. Rem 700 HBR rifle is about .010 below the rim of the bolt

2. One of my Custom bolt's pin is about .010 above the lip of rim of the bolt

3. Another Custom bolt is about .025 above the rim.

I used feeler gauges to determine, as best I could. the pins that rose above the rim ot tip of the bolt. With the Rem I measured with my vernier caliper's depth function.

NOW, I don't have any way to accurately trim these pins. I am loath to file them and even more loath to grind on them. I have a small lathe but it is very crude and not accurate and I don't have a Mill or surface grinder. What should I do and is the Remington correct being below the rim of the bolt?

Thanks,

Pete
 
With regard to the cams

I understand the relationships. It's been a while since I watched that video on utube so I don't remember exactly how close the cam surface on the bolt should be to the caming surface on the action. I don't think It matters much in my case, all the bolts extract the cases but it annoys me there is so much space between those two cam surfaces.
 
I grind the tip off with a belt grinder and radius the edges of it with the belt. I'd remove a little bit by little bit until it quits hanging up when you push the cartridge into the chamber. I need to do that on my Farley as I didn't shoot it at St. Louis because it the ejector was hanging on the cartridge case. You don't notice that so much when you're in the shop, but when you're shooting at the range is when it's noticable.

Does one of your's seem to hang up more than the other?
 
Yes,

I think the longest one is the toughest and I have had more problems with that rifle working well than any of the others. The second would be the next longest one. The one that is flush with the end of the bolt works great with lapua cases but not so well with Rem and Winchester. Even though they measure about the same as I recall, the lapuas work better.

The reason I went this direction is I saw a shooter of some note shoot 5 record shots in less than a minute and I was hooked. I thought if I did only not have to handle spent cases I could get 5 off in some of those hanging conditions that don't repeat often enough. I sold my RBLP rifles to go to RRR's. To date, none of them have been reliable enough to count on them in the Heat of Battle. Two of the rifles i sold were Lazers. Having two at the same time lulled me into believing they ALL were lazers. Silly old man !

I recently took delivery on a RLR. I like it fine but it isn't 100% and not even 90% reliable to count on running a condition; another disapointment.

I appreciate your help with this. I don't have a belt sander but should buy one and this is a good reason :).
 
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I am really happy with my Viper drop ports. I add a funky looking case deflector on the bottom of the stock to throw the cases into a tray on the right side of the bench so the cases are not under my left hand that is on the joystick. I did have one situation last Sat where a case got stuck in the drop port and the next fired case didn't have anywhere to go. I had to wiggle the cases to get them to fall through. You would think that the recoil of a 30 would shake the case out of the port. Has only happened this one time.
 
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