im currently in the process of building a custom single shot rifle in 408 cheytac. Im contemplating the bolt lugs between a 3 lug design(lugs offset by 120 degrees)and the conventional 2 lug rem 700 style just scaled up of course. what is your guys opinion between the two? also have been looking at the buttess style threads used on the Barrett m99.
bolt lug design
- Thread starter bbsharpshooter
- Start date
Re: bolt lug design
yes i am, i have the three integral lugs cut in the barrel extension, im just contemplating a 2 vs 3 lug design
yes i am, i have the three integral lugs cut in the barrel extension, im just contemplating a 2 vs 3 lug design
Re: bolt lug design
Well if your barrel extension already has 3 lugs cut into it then why would you even consider the bolt lug to only have 2 of them?
No disrepect intended but are you sure you have the knowledge, metal alloy properties and machines to build an action that will be safe to operate?
I only ask because the following is a direct quote from you in your other thread...
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bbsharpshooter</div><div class="ubbcode-body">thanks for the replys. i guess a better question is the remington 700 mlr in 338lm a longer action that the standard 300 win mag action. im looking to do a 338 build on a budget unfortunately i cant afford a surgeon, stiller, ie..action. who makes a mass produced action that can be made top adapt.</div></div>
Also to change the subject sorta...The 408CT is substantially more expensive to deal with than the 338LM and the 408CT is like 5 year ago news
Thanks
Well if your barrel extension already has 3 lugs cut into it then why would you even consider the bolt lug to only have 2 of them?
No disrepect intended but are you sure you have the knowledge, metal alloy properties and machines to build an action that will be safe to operate?
I only ask because the following is a direct quote from you in your other thread...
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bbsharpshooter</div><div class="ubbcode-body">thanks for the replys. i guess a better question is the remington 700 mlr in 338lm a longer action that the standard 300 win mag action. im looking to do a 338 build on a budget unfortunately i cant afford a surgeon, stiller, ie..action. who makes a mass produced action that can be made top adapt.</div></div>
Also to change the subject sorta...The 408CT is substantially more expensive to deal with than the 338LM and the 408CT is like 5 year ago news
Thanks
Re: bolt lug design
later,being the fact im a machinist utilizing cnc machinery ishouldnt have to much of a problem. i current have a nice piece of 300m( fillet mignon of 4340) 2.250" in diameter. here is a pic of a rough prototype of my 3 lug extension. just looking for peoples opinion o
n bolt lug design
later,being the fact im a machinist utilizing cnc machinery ishouldnt have to much of a problem. i current have a nice piece of 300m( fillet mignon of 4340) 2.250" in diameter. here is a pic of a rough prototype of my 3 lug extension. just looking for peoples opinion o
Re: bolt lug design
BB I had assumed you had knowledge of machining process but honestly that is not all of the equation of safety here. You have to be concerned of the heat treatment on bolt, firing pin, etc etc. (I am no machinist nor can build a damn thing)
I prefer the 3 lug systems but the high pressure cartridges can cause the bolt throw to be harder than the 2 lug systems. You also have to "finagle" the ejector, extractor placement to match the ability to get case out of ejection port.
Thanks
BB I had assumed you had knowledge of machining process but honestly that is not all of the equation of safety here. You have to be concerned of the heat treatment on bolt, firing pin, etc etc. (I am no machinist nor can build a damn thing)
I prefer the 3 lug systems but the high pressure cartridges can cause the bolt throw to be harder than the 2 lug systems. You also have to "finagle" the ejector, extractor placement to match the ability to get case out of ejection port.
Thanks
Re: bolt lug design
Very cool that you have both the knowledge and the tools to attempt something like this.
There are some underlying factors here:
-- The mechanical work needed to cycle the action Vs. the number of degrees (90 for 2 lugs, 60 for 3 lugs ect). The 2 lug design should be a little easier to make a nice smooth Lift-cycle rearward-cycle forward-finish chambering round. The 3 lug design should make for a shorter, "Harder", initial bolt open cycle. Barnard is reputed as being quite smooth, and Sako too is said to be pretty reasonable. Both are 3 lug of course, so it seems to "simply" entail more head scratching engineering to make it nice and smooth.
-- Cock on Open like most all modern actions, or Cock on close like some of the old military actions. Me personally if I am not cocking on open, it should make for a smoother initial cycle. For me, I don't mind cock on close because I already have easy momentum on my side. I would love to hear *REAL* operators thoughts on this actually!
-- Controlled round feed or not? Heh, yeah that is a loaded question! I think a 3 lug design pretty much negates any possibility of that. Sako style extractor, or the pinned M16 type? Many smiths believe that the M16 is a little more field rugged / friendly. The Sako *Could Possibly* come flying apart due to the fact it is not pinned in. Then again I guess you could use the bone stock Remington type extraction menthod.
-- Floating, self aligning bolt head, or not? I think 2 Vs. 3 in the regard is a moot point. Just putting it out there. The floating design should make for a more forgiving design from tolerances ect. The Hard and Precise method might be a bit stronger? It would seem Production wise Savage and their floating bolt head works pretty well in the field, for accuracy that is. Then again, at that point you would probably have to give up any idea of a M16 / Sako type extractor.
-- Lugs in the front only, or rear of bolt only? Lugs both front and back? How hard do you want it to be to machine, and how ungodly strong / safe? Hmm, Solid 3 lug front with M16 extractor, and "floating type" 3 lug rear! Bet that would be hell for stout! Complicated, and probably introduce "more to go wrong in field usage though". Then again, maybe Rem 788 type rear lugs to oppose your front lugs! /grin yeah I have an evil mind! But I have handled a Rem 788 and they function Very Nice!
-- To flute the bolt or not? Design the bolt with heavy fluting in mind or not? Fluting can allow a combination of Very tight tolerances, and it can allow for "a place for crap" to go, so as not to screw with operation in challenging field conditions.
-- Trigger mechanism, Firing pin, and Safety? One piece, two piece firing pin? Full on blocks the firing pin while in safe mode? Or will it just "Stop" the firing pin by a "Catch" method? Will you do your own trigger? One stage or Two stage? Personally I prefer two stage triggers hands down any day of the week, and that goes double down for the weekends! But hey, I am more than a bit strange right?
What type of methodology will you use to speed up the firing pin? What methodology will you use to ensure the firing pin is absolutely Field Robust No Matter What and Forever!
-- How will you handle Gas from a major case rupture? How will a catastrophic failure be handled? Cuts on both sides of the forward receiver? Bolt shroud like the old Japanese Arisaka? /grin... How safe do you want it by design, and in case of *OH SHIT* happening? The old Arisaka was considered by P.O. Ackley and friends to have been one of The Toughest actions ever! They had a helluva time blowing one up! Thing had a funky safety though...not saying I did not like it or nothing...
Personally, I would like 3 lugs (probably up front only, though front / back is a fascinating mental exercise), with an M16 type extractor. Cock on Close for me thanks. Should make for a smooth, fast, easy to operate action. It should be nicely robust for field usage as well. I have always loved the Winchester 3 position safety myself. Failing that perhaps a good tang safety, but those and GOOD can be a bitch to Really Do *RIGHT* in my opinion. Safety's are a pet peeve of mine, I prefer it to be just stiff enough that it Will NOT come undone by "Itself", but easy enough for me to quickly change the state of. It should be Out of the Way, but close enough to be easy... Hah! I cheerfully admit the Arisaka met most of that criteria, and also worked as a Gas escape safety for gasses coming back through the action! Was not all that smooth for the old war guns I had though! So, I prefer the Winchester 3 position all in all.
As I said, I think it is very cool that you are going to build your own action.
Gary
Very cool that you have both the knowledge and the tools to attempt something like this.
There are some underlying factors here:
-- The mechanical work needed to cycle the action Vs. the number of degrees (90 for 2 lugs, 60 for 3 lugs ect). The 2 lug design should be a little easier to make a nice smooth Lift-cycle rearward-cycle forward-finish chambering round. The 3 lug design should make for a shorter, "Harder", initial bolt open cycle. Barnard is reputed as being quite smooth, and Sako too is said to be pretty reasonable. Both are 3 lug of course, so it seems to "simply" entail more head scratching engineering to make it nice and smooth.
-- Cock on Open like most all modern actions, or Cock on close like some of the old military actions. Me personally if I am not cocking on open, it should make for a smoother initial cycle. For me, I don't mind cock on close because I already have easy momentum on my side. I would love to hear *REAL* operators thoughts on this actually!
-- Controlled round feed or not? Heh, yeah that is a loaded question! I think a 3 lug design pretty much negates any possibility of that. Sako style extractor, or the pinned M16 type? Many smiths believe that the M16 is a little more field rugged / friendly. The Sako *Could Possibly* come flying apart due to the fact it is not pinned in. Then again I guess you could use the bone stock Remington type extraction menthod.
-- Floating, self aligning bolt head, or not? I think 2 Vs. 3 in the regard is a moot point. Just putting it out there. The floating design should make for a more forgiving design from tolerances ect. The Hard and Precise method might be a bit stronger? It would seem Production wise Savage and their floating bolt head works pretty well in the field, for accuracy that is. Then again, at that point you would probably have to give up any idea of a M16 / Sako type extractor.
-- Lugs in the front only, or rear of bolt only? Lugs both front and back? How hard do you want it to be to machine, and how ungodly strong / safe? Hmm, Solid 3 lug front with M16 extractor, and "floating type" 3 lug rear! Bet that would be hell for stout! Complicated, and probably introduce "more to go wrong in field usage though". Then again, maybe Rem 788 type rear lugs to oppose your front lugs! /grin yeah I have an evil mind! But I have handled a Rem 788 and they function Very Nice!
-- To flute the bolt or not? Design the bolt with heavy fluting in mind or not? Fluting can allow a combination of Very tight tolerances, and it can allow for "a place for crap" to go, so as not to screw with operation in challenging field conditions.
-- Trigger mechanism, Firing pin, and Safety? One piece, two piece firing pin? Full on blocks the firing pin while in safe mode? Or will it just "Stop" the firing pin by a "Catch" method? Will you do your own trigger? One stage or Two stage? Personally I prefer two stage triggers hands down any day of the week, and that goes double down for the weekends! But hey, I am more than a bit strange right?
-- How will you handle Gas from a major case rupture? How will a catastrophic failure be handled? Cuts on both sides of the forward receiver? Bolt shroud like the old Japanese Arisaka? /grin... How safe do you want it by design, and in case of *OH SHIT* happening? The old Arisaka was considered by P.O. Ackley and friends to have been one of The Toughest actions ever! They had a helluva time blowing one up! Thing had a funky safety though...not saying I did not like it or nothing...
Personally, I would like 3 lugs (probably up front only, though front / back is a fascinating mental exercise), with an M16 type extractor. Cock on Close for me thanks. Should make for a smooth, fast, easy to operate action. It should be nicely robust for field usage as well. I have always loved the Winchester 3 position safety myself. Failing that perhaps a good tang safety, but those and GOOD can be a bitch to Really Do *RIGHT* in my opinion. Safety's are a pet peeve of mine, I prefer it to be just stiff enough that it Will NOT come undone by "Itself", but easy enough for me to quickly change the state of. It should be Out of the Way, but close enough to be easy... Hah! I cheerfully admit the Arisaka met most of that criteria, and also worked as a Gas escape safety for gasses coming back through the action! Was not all that smooth for the old war guns I had though! So, I prefer the Winchester 3 position all in all.
As I said, I think it is very cool that you are going to build your own action.
Gary
Re: bolt lug design
what about something along the lines of bill holmes 50 cal, or the gun metal designs big 50?
what about something along the lines of bill holmes 50 cal, or the gun metal designs big 50?
Re: bolt lug design
Personally I believe that the two lugs up front, plus a third in the rear is an advanced design. Savage owners on the Hide point out that their rifles are often as accurate as a GAP rifle, and are less finicky about loads to boot.
I suspect that the Savage floating bolt head reduces vibrations of the bolt. A well made three lug bolt, with the third in the rear, would probably stabilize the bolt, just in a different manner.
The new Barrett MRAD also has a floating bolt head. However part of this may be so that it is easy to switch calibers. These rifles are supposed to be extremely accurate.
My personal opinion is that the two lug design is strange and not fully mechanically sound. It may be vibration in the bolt, it could be something else. However securing the rear of the bolt does seem to be an advantage. Prairie Gun Works and Precision Shooting Sports (2009 Hide build) both have a lug in the rear.
Personally I believe that the two lugs up front, plus a third in the rear is an advanced design. Savage owners on the Hide point out that their rifles are often as accurate as a GAP rifle, and are less finicky about loads to boot.
I suspect that the Savage floating bolt head reduces vibrations of the bolt. A well made three lug bolt, with the third in the rear, would probably stabilize the bolt, just in a different manner.
The new Barrett MRAD also has a floating bolt head. However part of this may be so that it is easy to switch calibers. These rifles are supposed to be extremely accurate.
My personal opinion is that the two lug design is strange and not fully mechanically sound. It may be vibration in the bolt, it could be something else. However securing the rear of the bolt does seem to be an advantage. Prairie Gun Works and Precision Shooting Sports (2009 Hide build) both have a lug in the rear.
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