AIAX 6.5 CREEDMOOR

[Dellboy]

Having bought the AI 308 I decided to add a 6.5 barrel to it so on 10^th May I dropped it off to Dave at Valkyrie Rifles for the job (after all he is the UK only service agent plus I had spent time at the Birmingham show talking about it) .Got a text on 14^th May saying it was off to proof, ready to collect by 31^st May. Couldn’t get to pick it up till 11^th June (it’s a fair way to Rotherham from Essex.

Finally shot it on Saturday at Bisley, zero at 100 yards then 10 rounds at 500 in the afternoon it was V Bull 6 out of ten and just on the line for the rest .With the S&B ammo . Early next month its 800 and 1000 so it’s more of a test plus it will be wearing its moderator. Loving it .But the problem am I looked at a straight pull AR and well its already on next year’s ‘only need another 2 guns list’.

Thanks Dave

[lapua]

Why did he need the rifle, couldnt he just do a barrel? After all, AI dont send a full rifle to the proof house every time they get a barrel done. I thought proof house had some sort of action there specifically for AI barrels?

[baldie]

 

The proof house don't have slave actions.

I prefer to machine the barrel for the rifle its going to be used upon. You only have 0.004" between Go and No Go, and different bits could possibly vary. Thats why the factory always stipulate any barrel bought must be checked for headspace before use.

I've seen, several times, aftermarket barrels, made to a drawing, that dont headspace correctly.

Not really an issue on a new gun, but on an older one that has seen some use, the breech ring could be worn [ its designed to wear before the bolt lugs, and as thus, can be simply replaced when out of tolerance ]

[lapua]

21 minutes ago, baldie said:

 

The proof house don't have slave actions.

I prefer to machine the barrel for the rifle its going to be used upon. You only have 0.004" between Go and No Go, and different bits could possibly vary. Thats why the factory always stipulate any barrel bought must be checked for headspace before use.

I've seen, several times, aftermarket barrels, made to a drawing, that dont headspace correctly.

Not really an issue on a new gun, but on an older one that has seen some use, the breech ring could be worn [ its designed to wear before the bolt lugs, and as thus, can be simply replaced when out of tolerance ]

Thanks for clarifying. So how do they proof the barrels from AI?

[Dellboy]

1 hour ago, lapua said:

Why did he need the rifle, couldnt he just do a barrel? After all, AI dont send a full rifle to the proof house every time they get a barrel done. I thought proof house had some sort of action there specifically for AI barrels?

I wouldnt want a barrel made to fit any gun i wanted it to fit mine , as said above really theres a lot of tolerances that could affect the fit and performance , this way that barrel fits and works with that gun . The only problem now is learning to use it all properly . I am currently the weakest link . 🤔

[Catch-22]

Slightly off topic, but the Impact Precision 737R actions are all made to such exact specs that all  barrels chambered and threaded for them are done using CNC machines and never need to be headspaced for each individual action.

Simply buy a barrel off their shelf and screw it on your action. 

Interestingly I’ve heard from a couple of gunsmiths, who CNC chamber barrels for the Impact actions, say that they cannot do the same procedure for other custom actions, including Defiance, as the tolerances simply aren’t identical action to action, like the Impact’s are.

The above is one of many reasons why they’re the preferred action used in the PRS league as those guys go through 3-4 barrels a season.

[Dellboy]

20 minutes ago, Catch-22 said:

Slightly off topic, but the Impact Precision 737R actions are all made to such exact specs that all  barrels chambered and threaded for them are done using CNC machines and never need to be headspaced for each individual action.

Simply buy a barrel off their shelf and screw it on your action. 

Interestingly I’ve heard from a couple of gunsmiths, who CNC chamber barrels for the Impact actions, say that they cannot do the same procedure for other custom actions, including Defiance, as the tolerances simply aren’t identical action to action, like the Impact’s are.

The above is one of many reasons why they’re the preferred action used in the PRS league as those guys go through 3-4 barrels a season.

CNC machining wont make all the actions identical ,unless of course there is no tool wear i suppose ?  Although the batch numbers would be low enough to make variations mimimal maybe .. Interested to know what the acceptable tolerance would be for them ..

[lapua]

1 hour ago, Dellboy said:

I wouldnt want a barrel made to fit any gun i wanted it to fit mine , as said above really theres a lot of tolerances that could affect the fit and performance , this way that barrel fits and works with that gun . The only problem now is learning to use it all properly . I am currently the weakest link . 🤔

But the barrel that came with it was made to fit any gun😜

[ColinBR]

29 minutes ago, Dellboy said:

CNC machining wont make all the actions identical ,unless of course there is no tool wear i suppose ?  Although the batch numbers would be low enough to make variations mimimal maybe .. Interested to know what the acceptable tolerance would be for them ..

That's not quite true. 

If you want to go into real precision engineering, then tool wear can be compensated for during machining process.

Wither that be by temperature control or CNC probing and compensating plus other methods. 

Biggest factors tolerance wise can be seen between materials used and temperature management that material can handle. 

[Catch-22]

Worth a read.

https://precisionrifleblog.com/2018/12/29/custom-rifle-action/

The guys behind the Impact actions do engineering for NASA, Gov and Aerospace sectors, so know their shizzle about keeping tolerances tight and exact.

[Popsbengo]

CNC works to tolerances just like any other process machine. For sure a well set up, top quality and properly maintained CNC is pretty accurate and repeatable (tool wear compensation accepted) however CNC machining isn't inherently more accurate or repeatable than alternatives if jigging/fixturing etc is sorted.  Most CNC turning and milling use ball-screw driven by encoded axis motors - the point being is that the position feedback is indirect and subject to lost motion errors unlike a linear feedback digital readout directly coupled to the machine axis.  CNC is not the same as "super accurate".  

[ColinBR]

What alternatives are you talking about that are more accurate? 

[terryh]

Lapua

The London proof house goes down to AI and proofs them on site.

brgds Terry

[Popsbengo]

10 hours ago, ColinBR said:

What alternatives are you talking about that are more accurate? 

I'm not arguing "more accurate" I'm just saying CNC does not automatically equal magic accuracy.  For example, if you need to turn many components the same, a copy lathe will do the job.  A jig borer can be set up to gnats pubic hair accuracy, a match grinder (many made by the Swiss) will turn out near perfect components.  As you say, in-cycle gauging is valuable but not limited to CNC.

[Ronin]

I’ve built quite a few rifles on custom actions.

 

You can rely on Borden and Barnard (for instance) to allow barrel or bolt swap and correct headspace ( not between brands)

 

Both manufacturer seem perfectly able to maintain high standards of tolerance over a number of years 

I recently put a 2019 Borden Alpine action on a barrel that was machined by me in 2014 on another Alpine 

 

It fitted perfectly and headspace in tolerance.

[English]

On ‎6‎/‎25‎/‎2019 at 9:22 AM, Popsbengo said:

I'm not arguing "more accurate" I'm just saying CNC does not automatically equal magic accuracy.  For example, if you need to turn many components the same, a copy lathe will do the job.  A jig borer can be set up to gnats pubic hair accuracy, a match grinder (many made by the Swiss) will turn out near perfect components.  As you say, in-cycle gauging is valuable but not limited to CNC.

When I was an apprentice for a Swiss company, I visited a machine tool works in Zurich and was in awe of the size of the tables and machine beds used to machine pillars, tables,  the knee and many more parts of both horizontal and vertical milling machine's and CNC milling machines and lathe beds and gear cutters etc. I was even more surprised to find they were being machined on English Machine tools!

[Popsbengo]

3 hours ago, English said:

When I was an apprentice for a Swiss company, I visited a machine tool works in Zurich and was in awe of the size of the tables and machine beds used to machine pillars, tables,  the knee and many more parts of both horizontal and vertical milling machine's and CNC milling machines and lathe beds and gear cutters etc. I was even more surprised to find they were being machined on English Machine tools!

Those were the days!  We had a 100,000sqft of machine shop full of Brit. made machines but those manufacturers have pretty much all gone now.  Bugger.