Another way to keep lube on the lugs

[efm77]

"I would have hoped for more than a 1.5 safety factor myself, particularly in a consumer product meant for the masses w serious consequences both to life and limb as well as sales. But, in this case, the loading is well known and well defined by industry standards. And, the scapegoat is/will always be the ammunition or an obstruction. If factory ammo approaches that level, even remotely, it will be more to blame than the firearm. If it's not the ammo, then it's easy to say the bore was obstructed. If it's handloads, all manufacturer liability is out the door anyhow.

It would be interesting to know how the bolt was tested to a pressure of 150ksi if the receiver failed at 90-100ksi. I guess they used a purpose built receiver or some type of receiver reinforcement to get it to that level. Or maybe a hydraulic press or the like was utilized to load only the bolt face w the bolt head itself in a specialized testing fixture of some sort. I'd like the latter the best."



My understanding of the article was that they were referring to the action as a whole and not just the locking lugs. I've also read that Montana Rifle Co. have tested their actions to 120,000+ psi. I'll see if I can find the article from Dakota that I read and try to post a link if I can find it again.

[efm77]

Here it is:

http://findarticles.com/p/articles/mi_m0BQY/is_2_48/ai_81477150/

[steveinwv]

I don't lube the lugs on any rifle I have ever owned, other than a drop of gun oil, nor have 99.9% of the gun shooting world. Understanding that a small film of lube on the lugs is what does the job makes one realize that all of the extra lube is a dirt catching waste and a cleaning *****. Put a small drop of gun oil on the lugs and be confident that it doesn't magical disappear just because you can't see it, and enjoy shooting the gun instead of wasting two pages of internet site on an unnecessary milling/engineering debate.

[kslefty]

I use a single drop of 3 in 1 sewing machine oil for the same exact reason, nothing for debris to cling to.

[Smokepole]

While 3 in 1 oil is the bomb, neither it nor typical gun oil are high pressure lubricants. That's really the only reason I use the grease now. I have used just the oil for years w/o issues though. I guess it has a good bit to do with the environment the gun is operating in. Maybe a dry lube like graphite for sandy regions even. I'm sure the oil would be far better distributing for extreme cold.

It was not an engineering debate to begin with; I was merely posting a method different from what a vendor/site supporter here offers as a paid service. I explained why I liked it better. Then it became a debate. And, even if unnecessary, I surely hope my posts are as helpful or informative as Sharpshooters post w the pics. There's info and history there, that I would bet, flat cannot be found anywhere else. If you feel it is needless clutter, don't read it or bother to post; there's no one forcing you.

[Smokepole]

Finally got around to completing the simulations of this. The FEA analysis of the bolt head I modeled yielded results implying that a .030" radius on the back of the bolt head strengthens it about 4% over that of a sharp corner junction. I used bolt thrust loading approximating that of a 30-06. The FEA program simulates the Von Mises method of stress combination of shear and bending.

[steveinwv]

It was not an engineering debate to begin with; I was merely posting a method different from what a vendor/site supporter here offers as a paid service. I explained why I liked it better. Then it became a debate. And, even if unnecessary, I surely hope my posts are as helpful or informative as Sharpshooters post w the pics. There's info and history there, that I would bet, flat cannot be found anywhere else. If you feel it is needless clutter, don't read it or bother to post; there's no one forcing you.


Now you've turned it into an engineering debate. Let it go. Over a month has gone by, and it still doesn't matter in the real world. While I'm sure your "model" is correct, I think it is unimportant in this case. The rifle's receiver will likely fail before the bolt ever gives up, even with a square shoulder. Sorry to be so offensive.

[Smokepole]

Not offensive at all. You are correct based on what SSS said about the failure modes. I was just following up with what I had said earlier:

"If I have time, I'll 3D model it and complete the analysis both with and w/o the radius just for the heck of it."

And it's my thread. I started it. If I wish to speak about the reason why I like the radius on my bolt heads in engineering terms, it's my prerogative. This analysis is precisely why I, personally, choose to keep the radius, which is why I use alternate means to keep lube on the lugs. And that's why I ultimately started the thread.

[steveinwv]

Well said.

When you started "your thread" and posted on the WWW, I assume that you wanted someone to respond to it in a positive way. That doesn't always happen. A micro-thin film of lubricant of any sort isn't going to affect a square cut or a radius cut in a bolt thrust situation. I don't have to tell you, because I know that you know, bolt thrust is in a different direction than bolt rotation. Bolt rotation benefits from lubricant. Bolt thrust does not. And since the bolt thrust occurs well in front of any radius (or square cut), even that doesn't matter. The strength of the receiver does matter, at least where the lugs lock in. When the gun fires, it couldn't care less whether or not it has a square cut or radius cut bolt, nor could it care what type of micro thin film lubricant is between the bolt lugs and the receiver. Now once firing has occured, and if it has gone way overpressure, and if the case sticks in the chamber, and if you can lift on the bolt handle without it bending or breaking off first, and if the lubricant isn't sufficient, then maybe, and I mean a 1 in a billion chance, the square cut may shear before the radius cut. And that I am willing to say could have been helped by using premium lubricant.

[Bark]

Smokepole,I personally find that your posts here are a graphic example of why I have a long held addiction to precision shooting and I appreciate your time in their construction.Savage rifles as a breed seem to encourage a "hands on"approach and exploring the details is just a large part of the enjoyment for me.Well done.As far as the SSS/SP tactical tango goes,then end result is generally more than the sum of the parts,so feud-on and give us the good stuff.As a long running RSO I've witnessed countless times the guys who spend a bucket of hard earned on a custom rifle and then throw factory fodder down the tube,I don't get it.Guess I am just old and grumpy but rolling your own and developing the loads IS the art of the rifle.....you are what you eat.My guess is that those who feel you dive in too deep are the same guys that take their Harley to the dealer for an oil change.Yeah,ratta ratta ratta. OK,HERE'S MY ADD-TRY THIS STUFF,even on rails/lugs.Read about it,pick some up,and your world will change.I've tested every product thats come down the pike for over 40 years and this is exceptional and by far the most serviceable gun lube/cleaner I've found.Thats my say. http://gunzilla.us/ Old Grumpy Bark

Not offensive at all. You are correct based on what SSS said about the failure modes. I was just following up with what I had said earlier:

"If I have time, I'll 3D model it and complete the analysis both with and w/o the radius just for the heck of it."

And it's my thread. I started it. If I wish to speak about the reason why I like the radius on my bolt heads in engineering terms, it's my prerogative. This analysis is precisely why I, personally, choose to keep the radius, which is why I use alternate means to keep lube on the lugs. And that's why I ultimately started the thread.

[Smokepole]

"A micro-thin film of lubricant of any sort isn't going to affect a square cut or a radius cut in a bolt thrust situation."
No kidding?

"When the gun fires, it couldn't care less whether or not it has a square cut or radius cut bolt,"
Actually it does. It matters 4% as shown above. One could argue that the extras stiffness afforded by the radius adds to brass life, even if in a minuscule way. More strength under thrust makes it 4% more rigid, so the bolt surface doesn't flex back quite as much. It follows the brass would stretch less. We're talking practically nothing, but yes, the 'gun does care' as you put it.

You don't understand. I like lube on the lugs to prevent galling during primary extraction w stiff handloads and tight headspace. Many share that same sentiment. In fact, I've galled a lug on a Savage 10 after mistakenly setting the headspace too tight. It cost me .010" lapping off the integral lugs to clean it up. To keep lube on the lugs, something has to stop the baffle from wiping it away. SSS and many others simply turn off the radius at the juncture of the lugs and stem so that the wave washer can be relocated to there. That's fine and it works great, obviously. I've done that as well. I started the thread to show an alternate method. I believe it to be better, and for the afore mentioned reasons, however academic they may be. Other people (the guy w the pics) obviously like this way as well. Two roads to the same place. I didn't expect a response at all really; I just thought sharing the idea would be positive.

And thank you very much Bark. It's so very welcomed to see a non-argumentative post!

[johnsopa]

OK, I'm going to ask what's probably a stupid question...

For the guy that doesn't have any machining equipment at home (other than a Dremel :-) ), do I understand correctly that I cannot simply disassemble my bolt and move the wave washer up between the bolt head and baffle?

I ask because I sent one Savage action (out of six I have) to Fred to true up. When it came back, the washer was in between the bolt head and baffle. I called Fred to ask why and he explained it. Made sense to me. So, at some point when I make time, I was planning to move the washer forward on all of my bolts.

But it sounds like I can't do that without opening up the ID of the wave washer a bit, right?

[laportecharlie]

right

[TAB]

I have a 12 BVSS in .223 Rem, bought very lightly used, and as far as I know not modified. I just took the bolt apart to take a look at moving the wave washer. My bolt head has no radius cut - it is square, the body measures 0.464" dia. The id on the wave washer is 0.472" and fits between the bolt head and baffle very nicely.

The bolt head has the last four of the s/n etched on the bottom of the lug, so I'm guessing it is original. Next time I see the guy I bought it from, I'll ask if he squared up the radius.

Might be worth it to take a look and see if you have a radius cut bolt head or not.

TB