How important is hawing equal lug engagement on both lugs on a Remington 700 bolt or any bolt gun.
Gunsmithing Lug engagement
- Thread starter 40x
- Start date
Re: Lug engagement
thats a wide open question. Define what you mean by "equal", surface area, rotational contact....etc
Define "important" to what ?
thats a wide open question. Define what you mean by "equal", surface area, rotational contact....etc
Define "important" to what ?
Re: Lug engagement
Accuracy is a lot of little things that add up. Very few Remington's start out with full lug engagement. You can not lap the lugs into full contact. They have to be machined perpendicular to the bore of the action and the body of the bolt. Then lapping mates the two surfaces together.
Accuracy is a lot of little things that add up. Very few Remington's start out with full lug engagement. You can not lap the lugs into full contact. They have to be machined perpendicular to the bore of the action and the body of the bolt. Then lapping mates the two surfaces together.
Re: Lug engagement
The reason I ask is I had a very reputable gunsmith install a krieger 308 barrel on my Remington 700 he had blue printed the action and supposedly lapped the lugs in.As the years went on he rifle shoot great but I did noticed that the top lug was not getting the same wear as the bottom lug.Recently I sent the barreled action out to add 243 Winchester barrel I wanted to keep it as switch barrel project. The first thing my gunsmith did was he called me and told me that the lugs were not making equal contact. Now if he re-blueprints the action it will be a two barrel cost of installation or if I keep the action as is then there's only a charge of one barrel installation.My question is do I keep the action as is or spend more on it even though the rifle shoots really well.
The reason I ask is I had a very reputable gunsmith install a krieger 308 barrel on my Remington 700 he had blue printed the action and supposedly lapped the lugs in.As the years went on he rifle shoot great but I did noticed that the top lug was not getting the same wear as the bottom lug.Recently I sent the barreled action out to add 243 Winchester barrel I wanted to keep it as switch barrel project. The first thing my gunsmith did was he called me and told me that the lugs were not making equal contact. Now if he re-blueprints the action it will be a two barrel cost of installation or if I keep the action as is then there's only a charge of one barrel installation.My question is do I keep the action as is or spend more on it even though the rifle shoots really well.
Re: Lug engagement
You answered your own question. The rifle shoots really well. If it ain't broke don't fix it.
You answered your own question. The rifle shoots really well. If it ain't broke don't fix it.
Re: Lug engagement
It is not uncommon for the top lug on a remington not to make contact. If the bolt body to raceway is a sloppy fit the bolt will tilt up when the action is cammed closed, this causes the top lug to deflect away from its seat in the action. True the bolt raceway and install a properly sized (od) bolt and it will mitigate the deflection issue. I would also add that proper "blueprinting" is also needed to insure proper bolt lug contact
It is not uncommon for the top lug on a remington not to make contact. If the bolt body to raceway is a sloppy fit the bolt will tilt up when the action is cammed closed, this causes the top lug to deflect away from its seat in the action. True the bolt raceway and install a properly sized (od) bolt and it will mitigate the deflection issue. I would also add that proper "blueprinting" is also needed to insure proper bolt lug contact
Re: Lug engagement
If the top lug is making 70% of contact and the bottom is 100%. What negative effect can it have on accuracy?
If the top lug is making 70% of contact and the bottom is 100%. What negative effect can it have on accuracy?
Re: Lug engagement
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cpapa</div><div class="ubbcode-body">If the top lug is making 70% of contact and the bottom is 100%. What negative effect can it have on accuracy? </div></div>
You want a honest answer....9.9999 times out of ten none. It would be tough to prove even for the best bench shooters.
A good barrel, chamber and bedding will out shoot most drivers.
With that being said, to satisfy your quest you could always have both lugs lapped to 100% and sleeve the rear of the bolt to take any slop between the raceway and bolt body when in the closed battery position. Then see if your rifle shoots any better.
I'm with Dave if your are satisfied with the way it shoots, don't mess with it.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cpapa</div><div class="ubbcode-body">If the top lug is making 70% of contact and the bottom is 100%. What negative effect can it have on accuracy? </div></div>
You want a honest answer....9.9999 times out of ten none. It would be tough to prove even for the best bench shooters.
A good barrel, chamber and bedding will out shoot most drivers.
With that being said, to satisfy your quest you could always have both lugs lapped to 100% and sleeve the rear of the bolt to take any slop between the raceway and bolt body when in the closed battery position. Then see if your rifle shoots any better.
I'm with Dave if your are satisfied with the way it shoots, don't mess with it.
Re: Lug engagement
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cpapa</div><div class="ubbcode-body">If the top lug is making 70% of contact and the bottom is 100%. What negative effect can it have on accuracy? </div></div>
You'll never see it even if it did.
Unless you are going to ream the raceway and fit a new bolt you will never have even wear even if you have 100% bolt contact. And you can have 100% contact and have uneven wear. Just because someone sees "uneven" wear doesn’t mean you don't have 100%, or close to it, contact when the bolt is closed and locked up.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cpapa</div><div class="ubbcode-body">If the top lug is making 70% of contact and the bottom is 100%. What negative effect can it have on accuracy? </div></div>
You'll never see it even if it did.
Unless you are going to ream the raceway and fit a new bolt you will never have even wear even if you have 100% bolt contact. And you can have 100% contact and have uneven wear. Just because someone sees "uneven" wear doesn’t mean you don't have 100%, or close to it, contact when the bolt is closed and locked up.
Re: Lug engagement
a realy good gun builder and even better BR shooter (same guy) told me that he will not blue print rem 700 actions as its a waste of time he only laps the lugs lightly.
He swears that the accuract of the rifle comes from a good barrel that was properly fitted and finished and good bedding after that your can set the gun off with a hammer and it'll be accurate.
anybolt other than one with the "Borden bumps" is going to have some slop even it the bolt fit is .001" total clearance that gives your .0005" that the bolt can be pushed up in the rear and cause the top lug to seem like its not making contact
a realy good gun builder and even better BR shooter (same guy) told me that he will not blue print rem 700 actions as its a waste of time he only laps the lugs lightly.
He swears that the accuract of the rifle comes from a good barrel that was properly fitted and finished and good bedding after that your can set the gun off with a hammer and it'll be accurate.
anybolt other than one with the "Borden bumps" is going to have some slop even it the bolt fit is .001" total clearance that gives your .0005" that the bolt can be pushed up in the rear and cause the top lug to seem like its not making contact
Re: Lug engagement
So, what about the Savage floating bolt head. How does that relate to this discussion?
Greg
So, what about the Savage floating bolt head. How does that relate to this discussion?
Greg
Re: Lug engagement
Savages are null and void from discussion about any other "better" rifles due to their cheap cost and ease to work on.
Anybody who shoots a factory Savage in a match and does well is cheating !! LOL
I personaly have blueprinted a few Savage actions , squaring off the lug inside in relation to bolt bore along with action face and threads , then trued the bolt head , making the lugs and bolt face square with eachother. The rifle shot very well , in the .2" but it was in 6mmBR and the previous cal was 308 and it shot sub .5"
Savages are null and void from discussion about any other "better" rifles due to their cheap cost and ease to work on.
Anybody who shoots a factory Savage in a match and does well is cheating !! LOL
I personaly have blueprinted a few Savage actions , squaring off the lug inside in relation to bolt bore along with action face and threads , then trued the bolt head , making the lugs and bolt face square with eachother. The rifle shot very well , in the .2" but it was in 6mmBR and the previous cal was 308 and it shot sub .5"
