Rifle assembly

[Coyboy]

[ QUOTE ]
Unfortunately, I don't have the equipment to test such a system.......but my engineering background tells me it would work......

[/ QUOTE ]

Ah yes, I have put together quite a few mechanical systems in the last 13 years. The engineers draw it up and when I question the fesability of there plan, they always let you know who has the degree.

When it dosen't work they expect me to fix it for free. I don't think so!

I side with those that do, not those that ?think?

 

[buzzgun]

Kirby

If you cut a custom chamber specifically for a certain lot of match ammo......it wouldn't answer the question I asked.....now would it?

As far as other factors go....how many shots to a string, etc.....I can't give you that info because I wasn't there......

Since when did asking a simple question become "challanging someone about their products"?? It was a simple question for crying out loud! Sheesh! Is that a chip I see on your shoulder???/ubbthreads/images/graemlins/grin.gif


As I stated earlier......you asked what expensive rifle firing high intensity cartridge had a pressed in barrel system......I gave you a couple of examples......now, we have a group of your followers puffed up proclaiming you can build a more accurate rifle.....so what? Kind of funny that people become so defensive when I simply ask if your rifles can meet a standard......what's up with that??? I didn't say the PSG-1 would out shoot your rifles.....I didn't say your rifles couldn't meet the standard......I just mentioned that it had a pressed in barrel system and that it had to meet a certain accuracy standard.....and I asked if your rifles could meet the standard.......

Black Diamond

Thanks for the input......if you go back and read my posts.....I never said anything about the expensive rifle firing high intensity cartridges being a bolt gun or that it had the same type bolt/chamber arrangement as a bolt action....having owned several, I know exactly how the HK system works......I'm still not convinced that it's impossible to build a pressed and pinned system that would be as strong and as durable as a threaded system.....it may not be practical from a rebarreling point of view and it may be too expensive right now, but I have no doubt that it can be done....


Coyboy

I don't even know how to answer that post except to say....don't assume things about people you don't know..../ubbthreads/images/graemlins/grin.gif

 

[Black Diamond 408]

Buzzgun

I talked with a major action builder a few moments ago, i ran your ideas by him...here is what he said in a nutshell.

Great idea! First problem, the bbl would come loose eventully or blow off the receiver, even if pinned. You see its been tried allready and it failed, miserably he said! Threads are there for many reasons, one to keep the bbl in the receiver, second of which is ease for installation and repairs. The amount of stresses on the action and barrel are very high he said. Thread contact is also a determaining factor, the deeper the threads,within reason is the strongest, other factors on tennon size and action dia. Most current manufactures use 14-20tpi threaded tennons for safety issues. Extra fine threads were experimented with and found they were unrelialble. He said a properly threaded bbl to action fit is the strongest available due to the fact they become one. Press fitted bbls only will work on the type of guns i discussed earlier, with self suporting locking lugs or small cal rimfire rifles.

What it all boils down to is, a properly fitted bbl and action will be the strongest joint.

A pressed on bbl would be as straight as you could get it, but the joint is a weak link.

Dave

 

[Coyboy]

[ QUOTE ]
Fifty (and anybody else that knows the answers)

I'm trying to learn something here......

[/ QUOTE ]

Learn something? sounds like you know it all already, and are trying to convince everyone else.

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Can you explain why the precise threading you described above makes a big difference in accuracy????

[/ QUOTE ]

He answered that question and you are not yet satisfied.

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I guess I'm thinking like Ross......if the barrel/receiver faces are square and screwed together tightly, I don't understand why such precision threads would make any difference???

[/ QUOTE ]

Stop thinking and trust experienced machinist.


[ QUOTE ]
Does the barrel shank have to be threaded for the combination to be accurate???

[/ QUOTE ]

Sounds like you knew the answer to that question before you asked it.

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What if the inside of the front of the receiver wasn't threeaded at all, and the barrel shank had no threads either......could you machine each so that barrel to receiver assembly was a press fit, held in place by pins, and still be accurate??? Wouldn't that remove ALL clearance issues if you have no clearance???

[/ QUOTE ]

A tight press fit, the kind that would be needed for this degree of strenght, would most likly cause gaulling, which could lead to alignment problems.

If you want to know if a threaded conection is stronger than you press fit look in the Machenery's Handbook. Find out the tensile strength of a 1 1/8 X 16 class 3A thread. Compare that to the gripping force of your press fit and the
shear strength of a couple of 1/8" or 3/16" retaining pins. Also consider the fact that the threaded conection is tourqed to create a desirable preload in the conection. This preload would be almost imposible in a press/pinned conection.

I mean you no disrespect, but the consensus feels the threaded conection is the way it should be done. Feel free to do your own testing and research. When you design a better mouse trap feel free to rub it in.

 

[buzzgun]

[ QUOTE ]

I mean you no disrespect, but the consensus feels the threaded conection is the way it should be done.

[/ QUOTE ]

No disrespect??.....couldn't tell it by what you posted......consenses???.....when did this discussion turn into a vote on how things "should" be done????

How did this turn into and adversarial discussion??? I don't recall posting anything that wasn't respectful, yet people have jumped into this discussion like they had to defend something???? Strange.......

Advances in technology rarely come from people who focus on why things can't be done instead of how to do them........

Like I said.....don't assume things about people you don't know......

 

[Coyboy]

buzzgun, This post has got way off topic. It started with a simple question about prethreaded barrels and the steps to assemble at home. A couple of respected smiths gave the best answers they could to that question. You then came in asking why thread fit is so important. Nothing wrong with that.

Strangly it switched to pressed and pinned barrels and it no longer seamed to be about learning, more about teaching.
With some hard facts you may persuade someone, but your post were lacking in that area and things started to sound more like an argument. You are not the first person to think about pressed/pin assembly. For all I know P O Ackley tried it 60 years ago, I don't know.

If you were to reread this whole series you may see where it went south. Your realativly new here you hijacked a post. Suggested things based on how someone might take them.

The experience people on this site don't have to be here, but they chose to, and many of us appreciate the time they spend on this site. They contribute gobs of knowledge, and interesting projects that they are working on.

If you want to discuss the whole "How to fit a barrel, press vs thread" Start a new post and those that choose to participate will.

 

[James Jones]

Well Ross , I hope your happy now /ubbthreads/images/graemlins/shocked.gif !!!

Anyway , as for a conventionaly built rifle shooting against the PSG-1 for a 50 round conest , hell I will take an off the shelf Savage and with VERY LITTLE work , shoot against the H&K and win. Part of the reason its so expensive is cause its got H&K stamped on it !!

Like I said I have see several AR in both 223 and 308 that would shoot right with the PSG-1 , with factory ammo !!

 

[Chawlston]

[ QUOTE ]
[ QUOTE ]
Buzzgun,

Just curious if you could offer the makers of those expensive rifles that are using press fitted barrels with high intensity chamberings. I would like to do some research on their manufacturing techniques.

Kirby Allen(50)

[/ QUOTE ]

Ever heard of H&K PSG-1 or MSG-90 sniper rifles??? I believe the barrels are pressed fitted and pinned on them. The price tag on a new PSG-1 is over $10,000.........

If I remember correctly, there is a trunion welded into the receiver and the barrel is pressed into the trunion and then pinned in place.......granted, it's not a bolt action, but it proves that it can be done......


Thanks for all the input guys, I enjoyed the discussion ......sometimes, the only way improvements in a process are made is by questioning the reason the process is done the way it is!

[/ QUOTE ]

I sold my last NIB PSG-1 last year for 13500. There is no way they are worth that as a shooter. They were designed to dump lots of rounds on target in hostage situations. However, the design is over thirty years old and now we have other guns that can do it as well or better.

The PSG-1s were expensive from the factory due to the trouble and contiuous tuning to get them to shoot. Their price reflects the amount of time spent on them to pass muster at HK. Their barrels were not welded, the barrel was shrunk fit into a barrel trunion and the trunion was tack welded to the frame.

Steyr SSGs are preses fit as well. At least mine was.

The bottom line is that threaded joints will exceed the accuracy potential of any PSG-1 or Steyr SSG. I would be glad to demonstrate it to you if you have a PSG-1 or an SSG..

James

 

[buzzgun]

Coyboy


Despite what you may think.....I asked the questions to learn something......asking questions that challenge conventional wisdom is how we know if what we think we know is correct.....what's wrong with that???

As far as I can see, the thread went adversarial when YOU jumped into the discussion quoting what I posted and using it to apparently compare me to engineers who don't understand real world application......you added nothing of value to the discussion, simply a cheap shot at me.....

As far as hijacking the thread.....well, I asked a question related to the original question and the discussion took another direction.....hardly hijacking.....

I'm not trying to persuade anyone about anything......it is evident that some who posted don't care why something works as long as it does.....and it seems that some get a bit bent when someone not only wants to know that they work, but also why and how!

How long a person has been a member of a site is often brought up when someone can't think of any other way to discredit a person.....really rather funny.....I have never figured out the correlation between the amount of time a person has been a member and how much that person knows......I wonder how long Mike Bryant or Kenny Jarrett or JD Jones (SSK) or George Gardner or Chris Matthews would have to be a member before they were allowed to have an opinion??? /ubbthreads/images/graemlins/grin.gif

As far as starting my own thread about barrel/action joining......don't need to, we are discussing it here.....or did you miss that?? /ubbthreads/images/graemlins/grin.gif By the way, until you become the board owner or at least a moderator, I'll ignore any advice you give on when and where I can post....fair enough???

Thanks to Kirby, Dave, JDJones and Chawlston for adding some actual experience and knowledge to the discussion......if nothing else was accomplished, we at least made each other think!


Dave

I'd like to know who the action builder was that you spoke with, if you don't mind sharing his name?

 

[James Jones]

Buzzgun , I don't think that aybody was intentionaly trying to take cheap shots at you directly and I fully agree that with folks out their to question the way things are done and why their not this way or that we would probably still be hunting with rocks !!

I have given the idea of how guns were assembled alot of thought (probably way to much) and keep comming back to the "cost effective" reasoning.
Their was fella here just a short time back asking about whay barrels weren't made from a better material or even whay a gun wasen't made all in one piece ie. action and barrel. After this I gave it some though and looked at differant materials and differant processes and here is what I came up with , With all the right tools at my disposal , I could make a one piece action and barrel assembly out of 17-4 alloy ,which is very strong ,making all my critical dimentions a few thousands undersized , then send the whole thing out for heat treating and end up with a piece that is WAY harder and **** tough than any material currently being used , then using carbide or maybe ceramic tools final machine the thing all out. what you would end up with is a barrel/action that is 100% strait , the strongest assembly possible as its all one piece and made from a material that would give probably 200% longer bore life and capible of handeling pressure way higher than any conventional gun. Sounds pretty cool huh but if you add all the time and materail and the possibility that is might not work , you wouldeither have a $25,000 bad *** gun or a $25,000 tomato stake !!

back to the whole press fit idea , in my line of work I deal with alot of "interferance fit" parts and relize that they have their place and understand their limitations. I understand your line of thought about the slip fit being better but I know that the limitations of the slip it make it kinda unpractical , so here is an idea.

you get your Remington 700 action all setup and trued , the threads have been recut to 1.072" x 16tpi which is .010" oversized so your action is done. Now you get your barrel all setup and ready to thread and you thread it to a slighty bigger dimention say 1.075" thats .003" over sized. you know that from your precise setup and flawless attention to detail that the threads in the action are 100% true to the bolt raceway and the reciever face is perfectly 90 deg off of that and that the threads on the barrel are 100% true to the bore axis and that the shoulder that mates to the action is perfectly square , but those **** threads are just .003" to big , so we heat the action to say 350 deg and freeze the barrel to say 0 deg F. , the action will expand at least the needed .003" and the barrel will shrink maybe .001" so now they will screw together fine , so all is assembled and the barrel is torqued to the action and *** the to materials cool and heat back to room temp you have to perfectly mated parts that are threaded AND have the desired interferance fit. Next to welding the barrel to the action I can't think of a stronger setup ,now when the barrel is shot out and you want if rebarreled then you'll have a problem , will this gun shoot any more accurately than one that was simpy screwed to gether like normal? probably not , will it handel more pressure than the conventionaly built gun? NO , probaably less.

Like taking a Rem700 action and welding the piccatinny rail to the top , then welding the recoil lug to the action and threading it along with the action making a longer barrel tennon , replacing the bolt with a oversized unit to fit the precision reamed bolt race and TIG welding the bolt handel on what would you have ? a realy nice realy strong well built Rem 700 that you might be able to sell for $500 even thought you have $1000 in shop time in it , kinda a clone of the Surgen action that you can buy for a grand and sell for almost the same!!

Ross , whats costing you when you have a rilfe built ising the actual time that it takes to cut the action and barrel but the time it takes to dial everything in , going shop rate around here is $85-$100 per hr , and knowing whats involved in building a rifle , I say that you getting a deal !!

 

[NYLES]

I left out part of my x3 or just miss worded it...should have said 1MOA at a 100M may be acceptable where the x3 comes in is when we go to 300M and the MOA goes to 3.14"...

Kirby, I wanted to bet on you...and still would but wanted you to speak up on your own! Glad you did! I think you could beat it! /ubbthreads/images/graemlins/grin.gif

JDJ,
We gotta shoot Encores one day!

Buzz,
by no means did I intend to start a ****in contest my entire intent was to say ...Im not impressed with a 3.14 group at 300M...I would have stopped at 3 maybe tired 5 shots....I just see thier statemnet as hype! I was enjoying the post besides how else is AKA gunsmith going to build my next rifle and be on the cutting edge if people dont talk about things like How to put a barrel on!
SORRY!

 

[Pdvdh]

Well now... things were just starting to get exciting here and now it looks like the 'action' is dying down.

I'm an engineer too, however I'll quickly add that I don't design or build rifles for a living. I just like to own, shoot, and hunt with the accurate ones.

What I suspected early on in this thread was that the threaded barrel method was the more cost effective option for manufacture & construction, customizing, maintenance, fine tuning, and overhauling (rebarreling).

I just couldn't envision a press-fitted barrel assembly competing - cost wise - in any of these areas.

As this thread continued to develop, it became clearer and clearer that that was the bottom line. That threaded barrel to receiver assembly is being used because it provides a durable and high quality (accurate) product in a cost efficient manner, and allows for reasonably cost efficient retrofits, using equipment commonly available to gunsmiths all over the world. These cost efficiencies translate into practicality for manufacturers, custom gun builders, maintenance minded gunsmiths, and ultimately me - the consumer. There aren't very many final product designs that, when all is said and done, aren't dictated by cost.

NASA, the military, and some other government entities are the exception when it comes to cost consideration.

Now if this post rubs someone the wrong way, then maybe we'll get yet some more action outta this thread! /ubbthreads/images/graemlins/grin.gif Cheers!

 

[long action]

Buzzgun
I was a machinist for one of the largest chemical companies in the world for 33 years. Most of my work was on experimental proprietary projects.

I have machined just about every metal known to man. Including platinum, and gold. Tolerances of plus or minus .001 were considered a easy day. You could count on plenty of + - .0000. I have even made class 5 A bolts, and machined dodecagons out of titanium, And left-hand double lead internal Acme threads.

Now if you won't to talk to me about press fits. How about 10,000 pound extrusion barrel liners 12' long being shrunk in with .060' interference. That is a pucker factor fit.

Now I could probaly machine circles around most of the Gun Smiths on this board in a regular shop.

Now would I build my own rifle?. Hell no. That's what gunsmiths do.That would be like a brain surgeon saying I can take out my own kidney. I have had five custom rifles made. Each was a bargain, especially when you know what you are looking at.

Machining starts out as a trade then elevates to a art farm. There are so many hundreds of little idiosecrences that are fed from the machine to a man's finger tips it takes years to even began to understand what the metal and machine are telling you.

I am not trying to stop you from teaching yourself a rewarding trade. Just don't start with things that operate at 60,000 PSI and can double those numbers in a nano second

 

[Fiftydriver]

This whole topic is beginning to get a bit fiesty. Let me start by saying I apologize to Buzzgun if his comments toward me were taken in the wrong context.

We have two basic opinions here, one that thinks a press fit, pinned barrel may have great potential, and one that says basically it has been done and will not compete with a conventional threaded barrel.

In most cases, threaded barrels have been used as a means to cut costs on a rifle. At least in recent times with rifles that Joe Blow off the street would have the money to purchase.

Perhaps with modern technology there is a way to make a press fit barrel design that would function as Buzzgun says, I do not know if that is the case or not.

Basically the only comparision we have are high end military grade weapons compared to conventional threaded barreled bolt guns. Comparing the two head to head, there really is not a comparision consistancy wise.

Nor is there really a comparision as far as strength goes because there are no press fitted rifles I know of that are chambered in rifles much larger then 308. I may be wrong on this and if so, please point out my errors.

We are in the game of long range hunting here on LRH.com. Not that the 308 is not a fine little round and very useful in its performance relm but it will not make many short lists of preferred long range cartridges. By that I mean dedicated rifles designed for +800 yard big game hunting.

Discussions are fine but it seems we are loosing the aspect that this IS Long Range Hunting.com. When I read a post or topic and if I have something to offer in reply, I am looking at it from this point of view.

I am certainly bias about what I think are the best long range hunting calibers, no secret there, everyone has their own baby that is the BEST for them.

That said, if a rifle system can not handle say my 270 Allen Magnum loaded with a 169.5 g ULD RBBT at 3350 fps, and do so consistantly and accurately, I really have no interest in that system.

When I think about barreled receivers, I do not think of limits. I do not want limits, if a receiver design will not handle true long range cartridges then I am not particularly interested in testing the idea much farther.

I do not know if a press fitted barrel would work with say a 7mm RUM or 270 AM as minimum chamberings. In conventional diameter receivers and barrels, I would guess no it would not be strong enough for long endurance life.

Larger diameter barrels and receivers may have something different to offer because the larger the barrel shank, the larger the contact area and the better it would handle these stresses but still, is it practical.

Never a thing wrong with questioning how things are being done. That is always wanted and is the only way we truely advance our sport.

Anytime you think outside the box, you will also get hammered a bit as well, that is until you test your theories in the real world and prove them to be correct. Unfortunately that is the way it works. Bringing hard facts to the discussion is the only way to prove your theory to others who do not think the same way you do. If you offer hard facts to them and they still do not believe you, that is on them.

I really see this discussion going no where good from this point out. We all have our opinions, they have been stated. Some of us have alot of real world experience that we base our comments on. Others do not but that does not make their opinions invalid, just makes it harder to convince others is all.

When one says a press fit barrel is the best way to mount a barrel and others say no its not and then this is just repeated over and over again really does not offer much learning either way.

Its been a good discussion but it seems its reached its limits until theories can be tested and proven. I am sure there are test results out there on this. Finding them may be a trick but if anyone does, please offer what you find.

Until then, I have nothing more to offer to this discussion that will be meaningful in any way so I will just stop here.

Not worth bad feelings of any kind and it looks like this may be heading that way and its not worth that.

Good Shooting to everyone,

Kirby Allen(50)