Rifle assembly

[Fiftydriver]

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)

 

[Black Diamond 408]

Fifty,

Anything is possible, but iv'e never heard of any high quality rifle built that way either.

To get a real tight interferance fit .001?, just how hot would the action need to be for pressing? Most receivers are 43-46 RC, anything over the 700deg will destroy that. What if you wanted to remove the bbl and set back the chamber? What a nightmare that would be, prolly cut the bbl off with the lathe, then have to remove the stub from the receiver. Lots of ideas look good on paper, but in the real world???

hmmm SKS rifles has the pinned barrels, on the cheap models, the good ones have screwed barrels, ie russian made.

 

[buzzgun]

[ 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!

 

[Chawlston]

[ QUOTE ]
I'm in the process of obtaining a 338 Lapua for long range lead delivery.

I love the Sako TRG 42 but have a hard time with the cost.
In researching this it seems like it would not be to hard to assemble some well made parts and have an equivalent gun for significantly less.

I'm thinking of an AI stock, the new Predator XP action, Shilen select barrel, Jewel trigger and the misc minor components all based on the Rem 700 parts.

The action comes ready to go, the barrel can be ordered chambered and threaded on both ends, trigger is drop in as is the stock.

So what am I missing, where does the gunsmiths artful ability come in that adds a considerable expense to an already accurate gun?

Clearly I will need to develop loads, but is there something else that would make this hard?

Thanks,
Ross

[/ QUOTE ]

Square and concentric pretty well sums it up. The rest is attention to detail and OCD (obsessive compulsive disorder) when setting up the parts in the lathe for turning. Almost forgot..... You have to have decent equipment to do the above.

James

 

[Fiftydriver]

BD408,

I was thinking the same thing...

Kirby Allen(50)

 

[Fiftydriver]

Buzzgun,

I will make you a deal, give me 1/2 what that PSG-1 will cost and I will build you a bolt rifle that will out shoot it with a plain old fashioned threaded barrel.

TO be honest, for $5K you could get the rifle and a quality scope as well!! /ubbthreads/images/graemlins/grin.gif

While those rifles may or may not have pressed fitted barrels, I would be interested to see if they are more consistantly accurate then a quality built conventional threaded barreled rifle.

There may be a reason they cost $10K, it may be because of how the barrel is fitted to the receiver!!! /ubbthreads/images/graemlins/grin.gif

Again, I do not see an improvement here.

I am certainly not against trying unconventional things but I am only willing to invest the time and money on a new idea if it appears to offer substantial improvement on paper while looking at it with a realistic and practical point of view.

There are always risks involved with pushing the envelope in any area. I just prefer to have a fair likelihood that a new idea will be worth it before spending the time and money. In this instance, I would say I do not see the potential advantage but that does not mean it is not there.

Only one way to know for sure and thats in real world testing.

Kirby Allen(50)

 

[buzzgun]

Kirby

I have never owned a PSG-1, and would never spend $10k for one.....I'm happy with a bolt gun that shoots consistent 1/2 moa groups!

I have read that the accuracy standard that all PSG-1's must meet is 50 rounds of match ammo into an 80mm (3.14") circle at 300m. (1 MOA)!!! That's not a 3 or 5 round group, that's a 50 round group!!! Pretty amazing! Do you think your rifles could meet that standard??

By the way, I don't believe that H&K heats the trunion in their barrel pressing operation......my earlier comment about heating and press fitting a barrel was just a thought about how it could be done.....as to how hot the receiver would have to be to get the required expansion......well, that would greatly depend on the particular material used to make the receiver......and how much expansion was necessary.

Maybe somebody will actually try it someday........it would be interesting to talk to a firearms designer about the possibility.

 

[NYLES]

3.14 at 300M...50 round group? I dont understand the purpose, the group size is kinda big for 300m...and why would you need 50 shots to prove it?... whats the point?

Is that not a 1.33333333333 group at a 100M? Not acceptable in my book...and Im sure alot more in here will say the same! 50 round group, Ill bet there are ALOT of guns in here that COULD do it!

I also dont care to measure in moa I measure all groups in inches...are they claiming 1MOA at 300M? That 1MOA thing sounds catchy till you multiply it 3 times.

Hope not to offend the 10K rifle builder but they gonna have to do better than that. I think we like the "one for one" thing in here...50 round group is alot of shooting to say "ITLL SHOOT A 3.14" 50 SHOT GROUP AT 300M"! DId they do it non stop? Is it clamped down or Is there a dude out there that shoots pretty darn good? Didnt wanna rant but some advertising kills me! YOU FELLA'S carry on youve got a good read going on here.

 

[James Jones]

I have shot the PSG-1 that was owned and in service by the FBI , it is a fine weapon and for a semi auto it is very accurate , this gun would hold 1/2 moa out to 500yds with Federal match ammo. Is it worth $10,000 , hell no , in the same class their was a few AR that would shoot right with the H&K.

I have given alot of thought to the process of making rifles and how one could be made better , like the materials , desgine and so on , I have to tell you that it always comes back to the basics.

Their are alot of ways to skin this cat but for cost and function I can't see bothering wit any other way.

 

[bailey1474]

[ QUOTE ]
Pretty amazing! Do you think your rifles could meet that standard??

[/ QUOTE ]

I know his rifles (along w/# of smiths) could top this "standard." Lock both in a vise to eliminate all human error and I have a 6-250 that he built that will do that @ 400 yds. Easy.

 

[buzzgun]

Nyles.....

"I also dont care to measure in moa I measure all groups in inches...are they claiming 1MOA at 300M? That 1MOA thing sounds catchy till you multiply it 3 times."

Why would you multiply it 3 times????

MOA at 300 meters (328 yards) is about 8.7 Centimeters (3.4"), not 3 times that!

So, the PSG-1 is required to put 50 rounds of off the shelf ammo(not handloaded specifically for each rifle) into a sub MOA (3.14") group at 328 yards....that's 50 shots including "fliers".....not bad when you consider that it's a semi auto rifle......and, that is the minimum standard for accuracy.....I'm betting most shoot better than that!


That's all beside the point......the reason I even mentioned the rifle is because Kirby asked me which expensive rifle used a pressed and pinned barrel.......

 

[buzzgun]

[ QUOTE ]
I know his rifles (along w/# of smiths) could top this "standard." Lock both in a vise to eliminate all human error and I have a 6-250 that he built that will do that @ 400 yds. Easy.

[/ QUOTE ]

Will it do it with off the shelf "match" ammo that wasn't specifically worked up for that rifle???? /ubbthreads/images/graemlins/grin.gif

The PSG-1 uses a pressed and pinned barrel system...... that's why I mentioned the rifle when Kirby asked about an expensive and accurate rifle that uses this system.......

Maybe we can talk Kirby into chambering a rifle in 308 and letting us run 50 rounds of Federal Gold Medal match ammo through it and SEE if it can keep all 50 under 3.14" at 300 yards..... /ubbthreads/images/graemlins/grin.gif

I'm betting it just might do it and I'm volunteering for the job!! /ubbthreads/images/graemlins/grin.gif

 

[Fiftydriver]

Buzzgun,

A see, I have an advantage here, I would take your Federal Gold match ammo, build a reamer specifically for that ammo and the rifle would kick the hell out of a 1 moa accuracy standard at 300 meters.

You do not offer any other important factors however. Is this a continuous 50 shot string, is this 10 5 shot strings over a couple hours???? There are alot of ways to make up 50 round groups at 300 meters. I have 28 three shot groups from one of my 6.5mm WSMs fired at 200 yards and the largest group is 1.1" ctc. and all were fired at a 1" target square and all but 6 shots total were inside that square. Average group size for those 28 groups is 0.784" ctc and like I said, if you overlapped all 28 target squares you would only have 6 shots total out of the square.

Did I mention that was in a 15" barreled XP-100???

If the criteria was a 50 round group fired in a continuous string under a certain period of time with a hot barrel, I would be impressed, as an accuracy minded bolt gun maker, not so much, especially for the price tag.

How did a debate about rifle building techiques turn into challanging someone about their products??? If I was a bit warmer tempered I may have taken offense.

Hopefully it was all ment in fun, hard to tell reading a post so I give the benefit of the doubt.

Kirby Allen(50)

 

[Black Diamond 408]

The H&K rifle has a pressed and pinned barrel, but, the locking lug abutments are part of the bbl assembly, one reason why they shoot ok is because they use a high quality barrel. If the gun had a better receiver and threaded bbl im betting it would shoot even better. Their system is like the rem 742 where the bbl is part of the action to say. With the locking lug abutments part of the bbl, the stress is all on the bbl, not the action. No matter how heavy of a load the action stress is the same. I build an aluminum action similar to this. With a std bolt action rifle the pinned barrel will not hold up to the thrusts and pressures, this is coming from an action designer and builder. Basicly the bbl will eat away the pin eventully and loose the headspace. The only way this would work would be to design the action with a bbl that has the abutments in the bbl, the bbl would then be pressed into the receiver, but your not gaining anything. Almost all of the takedown military sniper rifles use some sort of bbl like this, the EDM Windrunner, Intervention, use a nut to hold the pressed in bbl on the receiver(refered to a Uzi style)

I have done a lot of tests on different materials for building actions, i can tell you what works and what dont.
It isnt being done because it would be dangerous. 10 tons of bolt thrust is a lot of pressure on just a pinned bbl. You might end up with a rocket fired spear.

I have shot several of these, from the G3 to the PSG-1, they all shot good for military rifles. No way close to a bolt rifle, our range is the midwest training area for law enforcement snipers training and certification, they take their 700rems, with factory ammo and consistanly shoot under 1moa up to 500yds. The semi autos will not do that, including the H&K rifles. My custom rifles will blow them and the 700rems out of the water. They have some really good shooters at these events and some even have custom rigs, 300win mags for this purpose. We dont mess around with the short targets, 500 and closer, we go to the 1000yd targets for our shooting. Our 1000yd groups look like thier 500yd groups.

Pinned bbls on a quality bolt rifle, i dont think it will fly, to many variables and potentially dangerous. Its been an interesting discussion, we cant compare the two types of actions in use here, one is stamped metal and the other is a precision piece.

Dave