Gunsmithing Cutting lug abutments and lugs

[ianagos]

So I'll be doing a little truing on my howa action before I rebarrel it. Now I get how to set it up but I was planning on just lapping the lugs in but I read that can cause problems in itself so I'd like to know what do you guys think about me just cutting the lug abutments while I cut the action face? Then I can cut the bolt lugs themselves and hopefully that will give me good contact but I'll prob just slightly lap to finish it closer. Anyways my only reason to not just go at it is action timing do you guys think that this will negatively affect the timing? I'm not interested in cutting the bolt to pieces to retune it nor do I completely understand action timing and therefore why I'm asking here. Thankyou guys

Note this will be a Howa 1500 short action and I'll be screwing on a pacnor barrel.

 

[fdkay]

before you go through all of that use some dykem or even a marker and check it first.
Lapping too aggressively can cause problems.

 

[Ledzep]

Not terribly familiar with Howas but cutting lug surfaces affects head space, can push back extraction cam surfaces, and can eventually make rifles head space off of the bolt handle (watch out). I'm with the above poster in checking engagement before you begin. If both lugs are making solid contact, I'd leave it alone. If one lug is floating, maybe look into fixing it.

 

[ianagos]

One lug is floating currently and I'm not worried about headspace as I'll be chambering a new barrel but when I get it set up I'll do as you guys say and check how far out it is. Now besides extraction can is there anything else I should worry about? Say maybe ignition timing? I know there are issues but I just don't know enough about it to say if I cut .003 off if I'll have issues. Thankyou so far for the help

Btw the Howa is very similar to the Remington just with features most people pay to upgrade on a remy. Like m16 extractor, it has a integral recoil lug, and lots of other nice things. But anyways that's besides the point. The lug abutments and bolt nose are very similar.

 

[Mitten]

If using a boring bar, just mark up the lugs and advance slowly until you have just cleaned them up, it won't cause an issue unless there already was one right on the border.

At PWS the actions are cleaned up with a reamer every time a rifle is sent back to be rebarrelled. There are ones that doing this over and over have moved the bolt back so far that the rear part of the bolt handle slot needs to be filed away from the handle hitting it. You can move it back far enough to get light strikes, but I have only ever seen that happen once, usually the raceway will code it out well before that and you will have lost nearly, or all, primary extraction by then. Now I am NOT saying you can not end up with problems, only that most of the actions on the M40's have been trued many times and are still accurate and reliable enough to be sent into combat with a sniper.

 

[ianagos]

If using a boring bar, just mark up the lugs and advance slowly until you have just cleaned them up, it won't cause an issue unless there already was one right on the border.

At PWS the actions are cleaned up with a reamer every time a rifle is sent back to be rebarrelled. There are ones that doing this over and over have moved the bolt back so far that the rear part of the bolt handle slot needs to be filed away from the handle hitting it. You can move it back far enough to get light strikes, but I have only ever seen that happen once, usually the raceway will code it out well before that and you will have lost nearly, or all, primary extraction by then. Now I am NOT saying you can not end up with problems, only that most of the actions on the M40's have been trued many times and are still accurate and reliable enough to be sent into combat with a sniper.

Ok the plan is to just sneak a boring bar in there and cut it if need be. Anything else I should true besides the action face and actual bolt lugs?

I don't have the tools or time to ream the action and sleeve the bolt so that's out. Is bolt face truing recommended? I wasn't planning on it.

 

[Mitten]

It depends on how far out the bolt face is. Measure from the front of the action to the bolt face in multiple spots (after truing and lapping) and if you are in by 0.0005 across the face I would not bother. If more than a half thou out it probably would be a good idea. But at this point we are getting into what are you trying to get out of it territory. If a bench rest gun, it should be dead on. If a PRS or accurate hunting rifle then inside a half should be fine. If east coast hunting or just to shoot, then probably not a concern.

 

[ianagos]

It will be for a prs rifle but how would I make sure to hold the bolt tight against the lugs as I'm checking with the indicator? Or would you suggest a depth indicator and just measuring around?
Thankyou

 

[Yoteslayer50]

Just put action in a vise with bolt handle down then measure off of front of receiver with a depth mic and gravity will keep bolt lugs up against lug abutments if you take as little as possible off of the abutments most of the time you won't have any problems but there are always exceptions good luck

 

[Wannashootit]

Ok the plan is to just sneak a boring bar in there and cut it if need be. Anything else I should true besides the action face and actual bolt lugs?

I don't have the tools or time to ream the action and sleeve the bolt so that's out. Is bolt face truing recommended? I wasn't planning on it.

PTG has a truing cutter guide block for Howa actions. In this circumstance, since you're not single-pointing the receiver threads I would use a guide block and cutter to true the boltface if needed. This gets the boltface perpendicular to the receiver threads (and presumably the chamber centerline) rather than the bolt itself. In the absence of an "everything" blueprinting, I think it's beneficial to get that face perpendicular to what you have, rather than to a dialed in bolthead that likely is not perfectly perpendicular to the receiver thread. JMO, I'm sure others will feel differently...

 

[Straight Shooter]

I've built quite a few rifles off of Vanguard actions. I have never found one yet with the lugs not bearing evenly. Are you checking it with the trigger in place? If you are then only the lower lug touches when cocked. Most 2 lug actions are like this. Unnecessarily cutting on an action just removes the primary extraction capability. If it's for yourself it will be a lesson right out of the hard knocks book. I'd bet depending on how good your bolt setup is you will find the bolts lugs will be right on as well. I see more damage done by "truing" than most any other procedure on most semi custom builds. Vanguards and Howa's do not have the bolt head soldered on so to machine those lugs or bolt face out of square would be pretty hard to do. If you want to snug up the bolt running clearance you can Cerakote the bolt to lose .002" or bolt and interior of the action to lose about .005" clearance.

 

[ianagos]

PTG has a truing cutter guide block for Howa actions. In this circumstance, since you're not single-pointing the receiver threads I would use a guide block and cutter to true the boltface if needed. This gets the boltface perpendicular to the receiver threads (and presumably the chamber centerline) rather than the bolt itself. In the absence of an "everything" blueprinting, I think it's beneficial to get that face perpendicular to what you have, rather than to a dialed in bolthead that likely is not perfectly perpendicular to the receiver thread. JMO, I'm sure others will feel differently...

Personally even though a lot of smiths probably won't agree im of the opinion that the threads are not there to align anything they are simply to hold everything in place. The actual alignment comes from the trued receiver face therefor why the Remington lugs that are all sorts of tapers give people problems. So in my head I'd like to square everything to that face but I know in practice that's not 100% possible. Anyways Thankyou guys so far for all your suggestions.

 

[Wannashootit]

^^^^

Exactly my point...we're in agreement.
I was saying that rather than true your boltface to the receiver centerline- where the threads likely aren't true, to true the bolface to the receiver threads instead. By using a truing block, you're working with whatever the existing threads are- and the boltface is trued perpendicular to the breech of the barrel.

 

[ianagos]

^^^^

Exactly my point...we're in agreement.
I was saying that rather than true your boltface to the receiver centerline- where the threads likely aren't true, to true the bolface to the receiver threads instead. By using a truing block, you're working with whatever the existing threads are- and the boltface is trued perpendicular to the breech of the barrel.

Ah yes I understand now

You are right I get it now just had to get it through my head... anyways ills see how it goes I've yet to break the barrel off yet since my shop is being moved and I'm building a new building here pretty soon. But I guess I'll have to buy more tools. I guess 20 tons or so isn't enough lol. Thankyou guys so far I'll see if I can break the barrel off tomorrow and try the suggested measuring tips I heard here.

Also I bought these Howa rifles with kryptec camo hoping they would be blued and they are indeed a couple hours in paint stripper worked for one while the other action is still got paint stuck on like crazy another round of stripper should get it done. Then it will be duracoated while the other one will stay blued. Funny enough though the one that the paint won't come off entirely has a beautiful deep blue with zero scratches while the other one that is completely stripped has several scratches that were painted over and the blueing is not as rich.

Anybody suggest anything better then standard Home Depot stripper? Maybe brake cleaner although they don't make it how they used too.

Thankyou guys