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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.
Attachment 267439
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....
Oh yes and it's so easy to machine when you're used to 4140Quote:
Originally Posted by robhughes-games
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...Quote:
Originally Posted by akaroa1
as for scope: iron/open sights?
I wouldn't put 7075 in a pressure critical part.Quote:
Originally Posted by STC
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.
read again what i said.Quote:
Originally Posted by akaroa1
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
I cant shoot my bog standard Kimber Hunter 257R consistently well. I know it's capable. It's just hard to keep steady and tame. Im close to putting a heavier Tikka weight type barrel on it. Caliber to be decided. @Jaco is going to help me about that.
alright sounds good :-)Quote:
Originally Posted by akaroa1
I use the European Individual Proof Of Weapons data
It's has all the extractor slot chamber data for drillings rifle barrels in it
When you look at a drilling rifle barrel ( and this data ) you realize how paper thin they can be and still be accurate whith the two shotgun barrels to keep them stuff.
You can make a barrel stupidly light but at the expense of rigidity
A 7075 sleeve well fitted is extremely light and stiff.
It also conducts heat vastly better than carbon wrapping.
Carbon being very stiff and light but also a good insulator !
the barrel is comparatively lowly utilized compared to lugs though.Quote:
Originally Posted by akaroa1
How do you ensure barrel and 7075 liner stay together and ensure a uniform tension/compression (which is likely to be necessary for precision) over the barrel? Heat shrink? press fit? (imagine both difficult to uniformly do over long lengths) -curiosity only
Yes that’s the compromise of lightweights. I had a model 7 .223 in the past that I struggled to shoot well consistently. Lightweight, and thin proportions made it a tough proposition for top accuracy. The two centrefires that I now own are 8.9lb and 9.12lb. They’re lovely to shoot, and am far more consistent with them. They’re still a touch heavy, I’d be happy with 8lb on the nose for the best of both worlds.Quote:
Originally Posted by Tahr
The main culprit for the weight on my two shooters is they both wear very robust FFP dial scopes- 26oz each
Maybe try a heavier suppressor before you go that route. I mean if you just want to try a new cartridge in that rifle go for it but I am confident that if you are running a dpt suppressor if you put just 2x stainless baffles in your suppressor it will make a world of difference to the shootability. Extra weight at the end of the barrel will settle it down a lot. I shoot a few kimbers and the ones in the heavier cartridges all run heavier suppressors. They are tack drivers.Quote:
Originally Posted by Tahr
You’re back to my point made earlier. If you can’t shoot your rifle well consistently because its super lightweight requires a technique that’s difficult to replicate in different field positions then your weighting the attributes incorrectly.
Adding heavy brakes and suppressors is not something that I would or can do here. Al well balanced sporter and scope in the low 3kg range is shoot able, and able to be carried in the hand when needed.
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