Thread: Super light thinking

Originally Posted by Maxx

Wish mine still fitted.

Problem solved.
Lots of stretch and doubles as a man girdle

Just to put some perspective on actual weights, the Grendal sits currently 880mm in length and 6lb2oz (around 2.81kg) as I carry it but unloaded. Weight could definitely be shaved off it but it’s neither here nor there for me as it’s still light but balanced for me.



As a comparison, the Tikka 223, 18.5” barrel, at hunting weight, weighs in at 7lb12.5oz (3.23kg)



If you chose, say a 6mm of some description, is 5lb achievable but still usable??

Interesting. Here is a pic of my "donor" rifle, currently with a 16" barrel in 308, weight is 3226g (7 lbs) at this stage. A @Scott Cowan stock would drop it by about 400 - 450 gms. The current walnut stock is surprisingly nice, it weights 885gms, but is still quite "chubby" if not "clubby" especially compared with say a Mauser Kurz stock. A diet imposed with the horse rasp and auger might get it down to 600 gms?

It's going to get a 18" 6mm CM barrel, that theoretically adds a bit over the 308 but the Knox on the 308 is 27mm and we will use something like 26mm on the 6mm barrel, so probably it'll come out the same.

Yeah, could do a carbon skinned stock at around the 450g mark I reckon.
Could probably modify it to be a blind mag and drop a bit more weight if you don't mind that as well

Christ it's bloody hard to make an ultralight rifle

Just threw some parts on my postal scales
All pretty conveniently parts that could become a rifle ( with a hell of a lot of work ) and minus any way of holding it.
And it's sitting at 3 kgs

So an immense amount of stock reduction would need to happen
Or some very light exotic expensive materials would need to come on board.

That's an ugly but new 1:10" 308 barrel some amateur gun hack tried to profile which could loose a lot of length and a bit of diameter
A scope, base and rings
And a couple of lumps of 416 SS which could become a breech and receiver

Obviously I'm ( typically ) approaching this from completely the opposite direction

But once those bits of 416 are machines they will be way less....

Originally Posted by robhughes-games

But once those bits of 416 are machines they will be way less....

Oh yes and it's so easy to machine when you're used to 4140

And some 7075 will sneak in there and oh so light, strong and easy to machine

Originally Posted by akaroa1

Oh yes and it's so easy to machine when you're used to 4140

And some 7075 will sneak in there and oh so light, strong and easy to machine

receiver and bolt body from 7075. only the pressure bearing parts from high tensile steel would be one way of shedding weight... but you need to know what you are doing there regarding sizing and strength calcs...

as for scope: iron/open sights?

Originally Posted by STC

receiver and bolt body from 7075. only the pressure bearing parts from high tensile steel would be one way of shedding weight... but you need to know what you are doing there regarding sizing and strength calcs...

as for scope: iron/open sights?

I wouldn't put 7075 in a pressure critical part.
Although I have used it for barrel outers with a pencil thin 4140 or SS inner barrel.
It does work well and has contributed to a couple of very light and accurate stubbed Contender barrels

My 20" Savage model16 in 22-250 with 3x9x40 gunworks suppressor and full mag of 3 rounds is bang on 4kg. I don't use a sling and it's either in hand or on pack, I haven't included the MTN Bipod as it's only put on when needed.

Must get around to weighing my M18 .308.

Originally Posted by akaroa1

I wouldn't put 7075 in a pressure critical part.
Although I have used it for barrel outers with a pencil thin 4140 or SS inner barrel.
It does work well and has contributed to a couple of very light and accurate stubbed Contender barrels

read again what i said.

parts under pressure must be out of high tensile steel.

Also its not just material choice but also design of those conponents, sizing, cross sections, pressure bearing, stress concentrators due to sharp corners etc. meaning they MUST be properly engineered...

Anybody that does not understand these factors should stick to proven and tested off the shelf components and not touch pressure bearing parts.

I’ve got an ultra light Kimber custom .260. Biased on MT Ascent, manner ultra light stock and ultra light Leupold 3x9x32 scope, talley lightweight rings. Plus a few bits of machining to smooth action and reduce weight. Wasn’t my build,bought it discounted, because guy who did, couldn’t pay the bill.
5lbs 2 Oz with 4 down,
It’s nice to carry,
Difficult to shoot consistently, very thin in the stock wrist, I am surprised I have not broken it yet.
Scope is not very good, in low light, but at 9oz for the scope, guess the lenses, aren’t not all that good.
I’ve got a Barrett fieldcraft in 6.5 creed, and a K95 in several calibre’s. these are in the 6 lb range, and are both much easier to shoot, and light enough to carry in the hand all day.
I wouldn’t do an ultra light rifle again, and definitely not bigger then .260, 6.5 creed, 708, with heavy bullets, they jump around in your hands plenty.

At one stage, I owned a Husky 98, in 9.3x62, 6lbs, with peep/ irons, shot very well, no problem with 2-3” group at 100m, but it sure battered me about step to far for a lightweight.

I did read it
But a barrel sleeve of 7075 is only a stiffener
The underlying 4140 barrel while pencil thin can contain the full pressure unsupported

I have all the chamber and barrel wall thickness tables and max pressure on hand.
All the liners are calculated for safe use with those cartridges at their maximum pressure and all have been proof tested