Bolt timing issues

[memilanuk]

So... Ive got a Target Action that I picked up from a friend years ago that has always shot pretty well, if not the smoothest.

I'm pretty sure the timing between the handle and the rear baffle is off a bit... after doing a bunch of reading here today I have a few things to test/try when I get home. One thing that kept popping up was folks tossing around numbers on how much primary extraction they (thought they) had... but I was left a little unclear on how exactly that was being measured?

Also, this particular action seems to have a bit more 'cock-on-close' than I'm used to, if that is the correct term. All my searches for that term returned a bunch of stuff on the B-mag, but not the 10/110. Maybe I'm not calling it the right name?

Lastly... after reading all this stuff, I have to wonder why aren't there places making matched sets of custom bolt handles + rear baffles, with the primary extraction cam ramp done right? [emoji55]

[Robinhood]

Due to tolerances in axial dimensions it is nearly impossible to get everything right under mass production constraints. this is why some action bolt combinations have PE issues. Why do you believe you have PE issues? If it is due to difficult extraction on fired cases all you need to do is stick a feeler gauge between the ACTION and the REAR BAFFLE. Go up in thickness until the case extracts easily. If you can't lift the bolt under any circumstance with a round or empty case in the chamber you have a different problem.

[RC20]

Sometimes you get two answers to the same question. You will have to decide which.


I am a bit of an outlier on this issue, but I do have empirical evidence to back it up.

My take is there is almost no, if any timing or PE problem. There is PEF (Primary Extraction Failure) or FTE (fail to extract) and that is a whole different story.

Its chamber stick that is the problem. My take is Savage chambers are not as finished as they should be (or we would like). Carbon builds up and the case sticks. The extraction on a Savage may not be as robust as other mfgs (that is speculative). All I am or was interested in was correcting and having seen the PE issue listed it made not sense.

As a mechanic/technician/engineer (no letters) tasked to solve problems like this I looked at it and there is a major amount of extraction distance with the ramp. It did not track that there was any lack there.

I had two new Savages that did just that. One about 2008 build and one new. I have done nothing to them other than make sure I clean the chambers and not just the barrel. No more problem. And the problem did occur after some firing on both guns.

A shift to Carbon killer 2000 seems to help as the chamber gets enough of it in it to keep them FTE free and proud for some time. We are talking about going from frequent to none.

A chamber polishing may help but cleaning the chamber corrected it in mine.

My two after market barrels have had none of that but I was into the cleaning regimens as well.

[Robinhood]

If you shoot old hard brass that never gets annealed you may have the problem RC20 has focused on. Hard brass does not seal on the neck. You will notice that your brass is dirty with carbon on the outside. Good brass will only have carbon on a portion of the neck. Both are very simple to recognize. If you brass is clean, try the shim method. If it is dirty try cleaning your chamber and anneal or change your brass. Now for one of several other difficult to extract issues that was not discussed is if the case has ejector marks on the base. You might want to back down on your load. So really there are not two trains of thought, there are several distinct issues that does not take an engineering degree to recognize, you just need to learn what to look for to identify your issue. Troubleshooting skills do help.

[m12lrs]

Well maybe this can explain it to you. I am having Fred work on one of my target actions now. Can't wait to compare the two when i get it.back. i have read this several times and i can understand the truing but get lost in the.timing. all i can say is if it improves bolt lift and cycling of the action i will be very happy.

Having him install his BR trigger too.

http://www.savageshooters.com/content.php?161-Fred-Moreo-Timging-Truing-Explained

[memilanuk]

Alright guys, ease up.

The gun is not dirty. The brass is not old, or hard. The loads are not hot. This is not my first rodeo ;)

Based on a *lot* of rounds down range with other Savage Target Actions, this one is just a fuzz off on the extraction. Every once in a while it doesn't *quite* extract as smoothly as I'd like - bolt lifts easy enough, but doesn't quite pop the case loose i.e. primary extraction. Now, moreso than in the past - had to change out one custom bolt handle for another, due to weight constraints - so I'm thinking maybe its a mis-match between the ramp on the rear baffle and the ramp on the bolt handle. The distance from the front of the bolt body to the bottom of the cut-out for the bolt handle is similar to several other ones I have handy - approx. 5.20x" - but the bolt handle is about as far *back* in the notch in the receiver/stock as it can get, on this one. On the other receivers, I can fit shims (feeler gauge at this point) between the rear baffle and the receiver, but if anything it makes the bolt lift worse opening up, and pushes things back to where the bolt handle won't *close* easily/at all, depending on the receiver. This one... I can fit 85+ thou worth of feeler gauge shims in, and still not make much change in bolt lift... but at that point, it does start having some issues with closing i.e. pushing the bolt handle back far enough it can't drop all the way into the notch.

And the other part of my question, which everyone has completely passed on... it seems to need a bit more force when it comes to closing, like something is camming home. When I strip the bolt down to just the body, the head and the handle (with the cross pin, firing pin and BAS to hold it to gether) - no ejector, no wave washer, no cocking piece or sleeve... the bolt handle drops freely on an empty chamber or with a 1.630" or 1.631" gauge in it. Won't close on a 1.632". Brass is sized to where it is just below a GO gauge, so the bolt handle drops freely on fired brass - its not hanging up on that either. I realize some of what I'm feeling with a fully assembled gun is the compression of the wave washer, the extractor clicking over the rim, and the compression of the ejector plunger... but this feels like more than that.

@m12lrs I have a couple actions trued/timed by Fred, one with his Evo trigger. I think those ones... probably didn't need much work done, cuz I couldn't tell hardly any difference when I got them back. This action, and a couple others... they might benefit more from his attention.

[Texas10]

I don't know if this is going to help you or not, so don't be bashful about hitting the back button if I'm seemingly off on a tangent.

Just picked up a very nice polished blue model 10 action from a member here. Smoothest Savage action I've had my hands on, but in checking it out, I noticed that it had a "catch" upon bolt close. The Bolt handle and rear baffle were black oxide, so it's possible they weren't original, but right at the point in bolt rotation where the bolt head is engaging the locking ramp, and the bolt handle/rear baffle is coming off the PE ramp, it wanted to lock up. Nothing a bit of force wouldn't overcome, but not smooth. And right at the point, I could not slip a feeler gage of any thickness between the rear baffle and action body. Too tight.

A bit of grinding and polishing on the PE ramp of the rear baffle and it's buttery smooth now on bolt closure, and extraction was found to be excellent once I put a barrel on it.

The machine work on those older actions is far superior to todays "one fast pass with a cutter and be done with it" actions. If the action feels and works smoothly, I can't help but think it's going to shoot better too. JMHOP.

[foxx]

I can't answer your question, memi, and I am not sure anyone can. (Doesn't mean it isn't valid or deserving consideration, I don't mean that at all). However, from what I can tell from Fred's work, is he gets the most out of the Savage design. He optimizes it. Depending upon what components you have to begin with, and how they interact, his work will will have various effect. The worse they are to begin with, the better his work seems to be. But, there is a certain point where no one can improve on them. If they are good to begin with, he can't make them better. If they are bad, he will get them to where they should be. As you said, you might have some now that will benefit more from his work than the others you had before.

Edit: Fred's work will make the best factory action better. How much better depends on how close it was to optimal to begin with.

[RC20]

Again this is a for what its worth view, supported by my experience and can be put in a trash can.

There obviously can be other causes, but I tend to think those are in the minority of the FTE problem.
I could be wrong, I could be right, I could be some place in between.

There is a miner industry with "fixes" out there to stop it. If I was making a fix for a problem and making money at it, I would happily continue to fabricate my fix and keep making money. The fix works, why worry?

My background is to get to the bottom of issues if possible and stop it at the root cause, not a fix that leaves the root still there.

Sometimes the fix (or patch ) is just fine, other times it just comes back to bite you.


Not being there for your second issue, simply no idea. I won't claim to be all that feel sensitive either..

What I can say is that my guns also were cleaned, the brass was new or just annealed (with a inductive annealed) an I had the FTE problem.

So I gave up the bore guide and put attention into cleaning the chamber. It stopped and has stayed stopped.

As things have evolved, so this is more a fast to the current thinking on the situation. Original thinking was a rougher chamber, but it was occurring after a bit of shooting.

However that also occurred during a period I transitioned to a modern cleaner from Hoppes.

Between the Carbon Killer 2000 and the Bore Tech Eliminator as well as getting a Lyman bore scope my take is that while the barrel looked clean, it was building up carbon I could not see.

The Hoppes never did completely clean the barrel, looking in the barrels you can see where carbon sticks in various places.

A slightly rougher chamber and carbon build up would seem to be the issue for my FTE. I have a sample of 3, so that is not an all inclusive statesman it applies to all. I think its worth doing it and finding out.

However I also did some test on the amount of extraction distance there is . Its a lot. Adding more with a shim give you more and may be enough to break it loose but while it gets you extraction it does not address the cause (assuming that the cause is sticking case)

While I know that an mfg can go off track, you can have stacking errors in mfg, I just find it impossible that Savage does not know how much extraction distance and or forcers is needed and fix it. This is not uncommon. I don't know of any way to know how much Force their design has over others.

But again, its gone from a 1 in 8 or so situation to none with attention to the chamber.

I believe the Carbon Killer 2000 helps that as its a far better cleaner than Hoppes was. I no longer keep getting a patch with a shade of carbon on it out of a barrel. The borescope shows very little (a trace here and there still)

The chamber does not tend to get cleaned that well unless you use a mop and there are no bristles on it so it makes sense it could build up carbon. Even off the gun the chamber is not easy to get a good look at.

As long as it does not build up I am ok with a trace. Hiding behind the lands down I in the groves.

What got me on the Carbon Killer and Bore Tech was an article by a guy who researched it and had a borescope to confirm results or lack of them. .

It simply outperformed anything else he tested (and I am not saying there are not equally good cleared out there, just vs what he tested)

I think Hoppes was an old brute force chemical approach and the Carbon Killer and Bore Tech are modern designed to deal with the Carbon specifically (and in the case of Bore Tech carbon and copper). Along with really working much better they are also odor free (Hoppes was SERIOUSLY bothering my wife to where I had to take the guns outside to clean) and non hazardous. Nothing but good as far as I am concerned.

So there it is for what its worth.

[m12lrs]

I love.the smell of hoppes #9. Brings back childhood memories

But i use boretech eliminator to clean my rifles. Best i have found yet. Gets the copper without the harsh chemicals.

[RC20]

Yep, I love Hoppes. Have a bottle still so I can get a whiff once in a while.

I will add that Bore Tech while advertised for copper, works on both copper and carbon (that would be important on a barrel that had layers of each built up)

I use the less expensive Carbon killer 2000 as most of what I have is carbon. I leave the copper alone unless I see build up.

Both are just wonderful. They work perfectly , and my wife is not suffering and I don't have to clean guns outside (no fun in the winter!)

[geargrinder]

You guys aren't listening. His issues have nothing to do with the chamber, carbon, copper, or anyting else like this. Monte is a high level competitive shooter, I'm sure he knows how to clean his barrel.


I jwrote and then deleted a bunch of stuff related to timing and cocking sleeves and pin. I went back and re-read what you said.

Is it possible that your bolt body is on the long side of the tolerance?

If it was, it would cause your bolt handle to run in back side of the slot. It would also give you some PE related issues since it is pushing everything further away from the rear of the action. The closing feel you are feeling could actually be the bolt handle interfering in the slot. When you put in the feeler gauge it would make it interfere even more because you are pushing it back further.

Measure this bolt body length against another SA bolt body. Or, simply try a different bolt body and compare where the bolt handles land.

[memilanuk]

Is it possible that your bolt body is on the long side of the tolerance?

...

Measure this bolt body length against another SA bolt body. Or, simply try a different bolt body and compare where the bolt handles land.

geargrinder,

Thanks for the response. I did compare the length of the bolt body against another one of a similar vintage (both early TA models, one for sure from before they went to CNC machining - that's been to England, Ireland, Scotland and Canada ;) - and this one, originally purchased years ago from a friend who was getting out of long-range after building a 7 WSM F-Open rig before such beasties were 'in'). Not sure if I was measuring at the wrong point; I measured from the front of the bolt body to the bottom of the notch in back, at ~5.20x", within a few thousandths on each. On the reference/control action, the (factory) bolt handle doesn't appear to be much if any further back/forward, but there is a very noticeable difference in the contact/wear point on the rear baffle/ primary extraction cam ramp - the wear spot is almost full width, though it is fairly short (in height). On the second action - the one actually in question here - the wear point is much less noticeable on the rear baffle, and given that the (aftermarket) bolt handle is brand new and Cerakote'd... there isn't much to see.

Monte

[RC20]

Swap bolts, swap handles, swap baffles..........................

The actual lift is very hard to measure (extraction distance).

Timing is a function of the baffle and where the rise starts (you want the lugs out of the recess before you extract)

I do seem to be missing something here (no unkind remarks, run on sentences (my English teacher would be appalled) and I need to pull it all out, break up, looks at a bolt in person and sort through it and I still don't know what 5.2 is? )

Good barrel cleaning does not necessarily mean a good chamber clearing if you are using a bore guide as it misses that

And the chamber is MUCH larger than the barrel, what cleans the barrel doesn't touch the chamber unless you work at it separately .

Its stuff to think about and explore if it seem applicable

[memilanuk]

The actual lift is very hard to measure (extraction distance)

Hence that also being part of my original question.


I do seem to be missing something here (no unkind remarks, run on sentences (my English teacher would be appalled) and I need to pull it all out, break up, looks at a bolt in person and sort through it and I still don't know what 5.2 is? )

Then perhaps this isn't the thread for you?


Good barrel cleaning does not necessarily mean a good chamber clearing if you are using a bore guide as it misses that

And the chamber is MUCH larger than the barrel, what cleans the barrel doesn't touch the chamber unless you work at it separately.


I do. End of subject. Let it go.



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[RC20]

Ahhh cut me to the quick. I hurt, I fall, I cry, I am (you know this was coming) baffled. Ok, I watch.

I will got back over the post and see where I missed you cleaned the chamber specifically.

I did do some measuring, have to look back. I think something along the lines of .050 - .060 extraction distance.

There is some take-up and looseness to accommodate.

The best method was a rod down the barrel but I needed more hands to get indexed right.

Something I learned a long time ago. Good at one thing does not mean good at another.

When they tried to do man powered flight (pedaling) they started with a pilot. The failed.

What they found was that piloting could be taught to almost anyone (see WWII). What they found was you needed an athlete (peddling). You can teach an athlete to fly, you can't teach a pilot to be an athlete.

I await with baited breath the answer.

[memilanuk]

I will got back over the post and see where I missed you cleaned the chamber specifically.

It's right around the part where you assumed I'm an idiot incapable of properly maintaining a precision firearm. And then proceed to blather on ad nauseum about anything *but* what I asked, despite several hints to let it go. Take the hint...


I did do some measuring, have to look back. I think something along the lines of .050 - .060 extraction distance.

There is some take-up and looseness to accommodate.

The best method was a rod down the barrel but I needed more hands to get indexed right.

Finally, some useful information.



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[Robinhood]

You should try explaining pump starvation, cavitation and what that does to the internals of a firewater pump in recirculation.

[memilanuk]

You mean dead-heading a pump? ;)

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[J.Baker]

Sorry RC20, but this gave me a good laugh. Clearly you don't know who memilanuk is, so let me give you a hint...

http://www.usrifleteam.com/monte-milanuk/