Lapping in a bolt...

[fgw_in_fla]

Would I be safe in assuming it's a whole lot easier to remove the action from the stock when lapping in a bolt?

It's not the lapping that concerns me. It's cleaning out the action & chamber after it's lapped. I can't help think polishing/grinding compound can do bad things to a barrel if not properly cleaned :o

Also, should I break down the bolt - ie.- remove the forward baffle & proceed. It looks like it might make it go a little faster / easier....

Any particular brand compound y'all recommend for this task?

Mucho Gracias,

Frank in Fla.

[sharpshooter]

Lapping the bolt is BAD idea. The floating bolt head assure that you get contact on both, no need to lap.

[ellobo]

Sharpshooter is right. Lapping a floating bolt head where you have close to perfect contact anyway lapping is an exercise in futility and totaly unesessary.

El Lobo

[fgw_in_fla]

I see on one side of the bolt it's real shiny.... The other side is shiny at the edge where contact is first made when locking the bolt head shut.

When I put a little grease on the contact sides, it's clearly getting rubbed/ wiped on the shiny side & the pattern is the same as the shine on the other side.

Lapping in the head won't help even this out?

I understand the concept of the float but this looks like it's barely making contact on the one side....

Whatcha think?

Gotta hit the sack.... See y'all tomorrow

[sharpshooter]

Most bolt lugs will always look like that. The reason is the generous clearance around the bolt body raceway. When you close the bolt, it is almost always slightly cocked to one side when you start to turn the bolt down. Being slightly cocked to one side, one lug will contact the closing ramp before the other one.
When the first lug contacts, it acts like pivot point until the other lug catches up. That's the reason for an irregular contact pattern. Believe me, when you pull the trigger, both lugs will get the same pressure.

[Blue Avenger]

no way are you going to get all the compound out, unless you remove the barrel to get back in the raceways.

[fgw_in_fla]

Sounds logical.... Especially the part Blue said about not getting all of the stuff out without a complete breakdown (possibly including nervous breakdown, too)... :o

Ya know, I had wondered about this subject. Some guys are adamant about even pressure on both side of the bolt but I can't help think with 40 to 50 thousand pounds of pressure when the round ignites would push it back nice & tight, as well as everything else.... Including my right shoulder.

Thanx for the info folks. It's much appreciated & you save me some work. Now I gotta find something else to work on. (Work on = tinker, fix, repair, modify, break if necessary, etc..)

Frank "No lapping compound in my action" in Fla. ;)

[jonbearman]

+ 10 for sharpshooter,he is the man.He knows these rifles inside and out.

[1jonzmith]

Most bolt lugs will always look like that.

I am new to the Savage world. And that is not to imply that I am expert in any other. I have always lapped my lugs to get a more perfect contact patch. Sure the ears were making contact on both sides and all the way around but..... they want 80% contact when in battery. The Mauser bolts with the ears fixed to the main body of the bolt cannot self center as the floating Savage can do. BUT, (big word that) I wonder that a case can't still be made for lapping the lugs.

After firing a cartridge the brass is left pressed back against the bolt. As you use a particular brass, this residual force will increase. After five firings or so with high powder charges, the brass will be so expanded as to need full body sizing instead of just neck sizing with the light shoulder bump. The tip-off that you need to full body size is that the bolt becomes hard to open. With "cock-on-open", you don't need anything else resisting the movement. Is it safe to say that lapping the ears to make opening the bolt easier won't be a waste of time? Even if that happens every four or five uses of a brass?

I have blued the bolt head and receiver of my brand new SS Target action. I was disappointed to see that I have a contact area that goes all the way around the ears at the point where they join the center shaft, that "patch" is a razor sharp fine line. At first I thought there must be a sharp protrusion from the ramp but the ramp also had the same signature. I am sending this off to Fred so I'll wait and see what he does with it. Please understand I am not doubting anyone here and a couple thousand posts means something...at least to me.


Believe me, when you pull the trigger, both lugs will get the same pressure.

I do believe you. Be assured of that.

[fgw_in_fla]

Since we're still on the subject...
Let me ask this of y'all - Purely hypothetical (I think)...

If a round is chambered, the bolt is locked and such, ready to fire and both sides (ears?) of the bolt are not touching the action fully & equally. Would this in anyway cause the brass to expand in a "less than even or symetrical" way?
Upon firing the round, brass expands to the limits of the chamber. Would the fact that the case head is not squarely locked in place cause it to expand "out of square"? (Sorry... contractor term)

Or, is this a scenario that happens such that everything - bolt, case, chamber, all - will all expand in symetric fashion & then settle back to their original dimension?

I understand what Shooter & everyone is saying. What I guess I'm trying to ask is can I squeeze that last little teeny, tiny drop of accuracy out of a rifle by bolt lapping? OR... is it really a complete & total waste of time & resources that would be better spent shooting, making ammo or talking guns with the guys, etc...?

I genuinely appreciate the info / input y'all do share ;)

Frank in Fla

[Blue Avenger]

Yup, have an enfield that is out of head space and dose that

[sharpshooter]

Most people will mis interperate the wear pattern on the lugs and lug abutments. When the lugs first touch the lug abutments, it will contact at the very outside of the ramp(as the ramps are cut at the factory) because of the manner of which there are machined. This will leave a contact mark to the outside of the lug as at this point the pressure is created by the compressing of the firing pin spring, aproxx 20 lbs or so. The ramp is not a perfect mate to the leading edge of the bolt lug, which is .220" ahead of the centerline. Once the innermost part of the leading edge of the lug is rotated past the inner most edge of the ramp, the load is now distributed more evenly, but may not be exactly centered.
What you are seeing and interpreting is rotational contact, not actually thrust contact.
Lug lapping is a old time method used to insure good lug contact to actions that have a fixed bolt head, such as a Rem 700. One of the problems with a fixed bolt head is that the trigger set up puts upward pressure on the rear of the bolt, tilting the lugs out of square. This is not an issue with a Savage, as the cocking piece engages on the side.
If you are worried about things being out of square when you chamber a round, consider this: The ejector will push a case to one side. At one time bench resters thought this was a detriment to accuracy, now almost everyone uses one.
Save your time and money and make better ammo.

[barrel-nut]

Save your time and money and make better ammo.


+1

[1jonzmith]

Most people will mis interperate the wear pattern on the lugs and lug abutments. When the lugs first touch the lug abutments, it will contact at the very outside of the ramp(as the ramps are cut at the factory) because of the manner of which there are machined. This will leave a contact mark to the outside of the lug as at this point the pressure is created by the compressing of the firing pin spring, aproxx 20 lbs or so. The ramp is not a perfect mate to the leading edge of the bolt lug, which is .220" ahead of the centerline. Once the innermost part of the leading edge of the lug is rotated past the inner most edge of the ramp, the load is now distributed more evenly, but may not be exactly centered.
What you are seeing and interpreting is rotational contact, not actually thrust contact.
Lug lapping is a old time method used to insure good lug contact to actions that have a fixed bolt head, such as a Rem 700. One of the problems with a fixed bolt head is that the trigger set up puts upward pressure on the rear of the bolt, tilting the lugs out of square. This is not an issue with a Savage, as the cocking piece engages on the side.
If you are worried about things being out of square when you chamber a round, consider this: The ejector will push a case to one side. At one time bench resters thought this was a detriment to accuracy, now almost everyone uses one.
Save your time and money and make better ammo.


Now that is true gunsmith wisdom and I never heard it before. Means only that I learned something. Thanks!

I have ruminated about all my Mauser actions having the bolt move up and down at the rear with the trigger pull. That problem exists, as was stated, on all Mauser based actions such as Rem and Win. The fix is to install a Timney Trigger or other aftermarket target trigger. Closely watch the bolt on the trigger pull and you will see no movement of the bolt in any direction until he pin hit the primer with the target trigger. A major reason why the Target triggers reduce group size even if the trigger is all you do. Thanks.

John

[1jonzmith]

Since we're still on the subject...
Let me ask this of y'all - Purely hypothetical (I think)...

If a round is chambered, the bolt is locked and such, ready to fire and both sides (ears?) of the bolt are not touching the action fully & equally. Would this in anyway cause the brass to expand in a "less than even or symetrical" way?

I genuinely appreciate the info / input y'all do share ;)

Frank in Fla


That gap you refer to is "head space" and that will allow the brass to "stretch" with the firing and that leads to brass failure where the head separates and you get molten steel blown back in your face at bullet muzzle velocities. That would be whether it is square or not. I can't speculate on accuracy impact but brass failure is a bigger and more pressing issue.

Maybe SharpShooter can recommend the best link to pictures and info on brass deformities and what problems they indicate. Bench shooters closely look at every ejected brass, most often right after it is fired, to detect pressure and other problems as soon as possible and prevent receiver failure..... (read that as death)

HTH

John

[fgw_in_fla]

Shooter - Thanks for the education. I've always wanted to sit in on a lecture of Savage 101. Your explanation was quite clear & concise.
AND - you just saved me a whole bunch of time which I can now spend on something a wee bit more constructive.
Thanks, again. ;)

Now, if you'll excuse me... I believe I'll go make some more ammo with some nicely polished brass. I mean after all, I have a little extra time to spend on it now...

[montrose]

I just got back from my FNG with a new Savage 11 TH .308 and I ran across this thread while trying to get advice on lapping my barrel, which led me to figure out lapping in a bolt. This is my one and only rifle after my childhood .22 nylon 66. Thanks guys for getting me off to a great start. Any further tips on breaking-in this gun?
Glad to be here,
Montrose

[fgw_in_fla]

Montrose - Welcome to your new addiction.
You may find a lot of info by doing a search on break in....

That's one of those subjects if you ask 10 guys that question, you'll get 12 different suggestions. Personally, I have never worried about barrel break in. I don't let them get hot & they get cleaned & de-coppered after every use.

A regular regimen of bolt clean & lube, check screw & bolt tightness, check barrel float & tang float (not that they move on a regular basis)...
A little wax, a little Armour-All, You'll have your own routine together in no time.
The important thing is to have fun with it. It won't be long before you too will have 6 rifles & 14 different caliber barrels you'll be reloading for.
It's the Savage OCD / Addiction. No one escapes.
Frank in Fla