To chop or not ?

Double four

Well-Known Member
Would like some advice guys, just bought a sako 75 in .308 22" and a bit long i think ?

Gone for an A tech cmm4 lightweight muzzle can after reading good reports on the site,
when when i put against the rifle looks like its going to be a "very" long beast!
Going to get it threaded this weekend and can't decide whether to chop it of at 20" while he is on with it or leave the length alone ?
Do you think the drop in velocity with the chop is worth it for better handling and handiness ?

I chopped my 75 varmint .243 to 20" and got round the velocity drop by going down in bullet weight seems to work fine, and accuracy from the short barrel is just as good as the long one.

But as .308s have a bit of a loopy trajectory to start with, would it be a good thing loosing fps over handling as i want to use the heavier bullets which will be going slow to start with ?

Your thoughts most welcomed .DF
 
i agree a cut for 2 inches isnt going to make much difference. i would save the dosh and keep it as it is
 
I took my 260 back from 22.5 to 20.5 inches. It made a huge difference to the handling of this rifle, particularly when you use one of the ultra light mods.
 
i agree with claret dabbler. i have a.308 cut back to 20 inch and am very happy .Fitted with an ase utra s5 mod it is no longer than a standard length barrel. if you are shooting at reasonable distance the .308 is not that loopy:)
 
Although not same calibre, I took nearly 4 inches off my .223 remmy and it handles far better when lamping,fits in the car better and it didnt make a rats arse to its accuracy...around 50fps per inch loss is the norm,
 
I have a Sako 75 in 30.06 had two inches chopped off it (recomended ) and it handles a lot better ,now having my Sako75 in.243 done the same.
 
If you are going to get it threaded, will they not cut and re-crown anyway? If so, shorten the barrel at the same time - you could even go 18" like the RPA but 20" would be good...
 
I had my .243 done but given the same option again I would have just swapped the mod for an over barrel type which are generally shorter infront of the muzzle. But thats just me and some people prefer a bolt on the end mod.
 
Went for the 20" chop in the end through advice from members mainly CD, got it back monday night tried it yesterday.
What a difference really impressed with the cmm4 au mod ,think i made the right decision even at 20 " its still a longish rife with mod attached.
Its a couple of inches longer than my choped .243 with predator 8 compact, but a whole lot lighter you just dont know its there.
Thought the noise level was on par with the pred 8, recoil drastically reduced didn't think it made it more accurate with the reduced recoil but what i did notice you can see the target after the shot.
Well worth doing looking forward to using it this weekend on the munties . DF

Comparison with over barrel and muzzle can both 20"

View attachment 5334 View attachment 5335
 
If you chop two inces off the end you will lose between 30fps to 50fps of velocity per inch removed. So if you are using 150gn BT's and using 46.2gn of Reloader-15 you will still be pushing 2750fps out of a 20" barrel. Not exactly slow ;)

Do it, it makes sense.

Simon
 
Those are two nice rifles Bob, glad you you are happy with the chop job.

The latest lightweight mods make a huge difference to the handling of a rifle. While I would not now use an unmod'd rifle in this country, the big old cans completely ruined the handling of rifles.

As flytie states, if you hand load, go for a powder on the fast side for your cartridge, Benchmark is well worth a try and you will minimise both noise and velocity loss.
 
Yes more than happy Brian thanks, the load that seems to work best in the sako is 46 varget 150nbt's.
if i shoot straight a cold dirty barrel will group three rounds touching , from cold clean 1st shot bang on the money the other 2 rounds touching no more than .75 group so im over the moon.

Dont know what speed this load does but i will get the chrono out nxt week and test it.

Thanks again to everyone who offered advice and thier experiences. DF
 
I tried to work out the speed my bullet is traveling out of a my 20" tikka varmint. With my backwards method of doing it as i no crono i think it doing about 2900fps?. I played around on sierra infinity6 messing around with zero hight and velocity to the drop chart matched how it was shooting, Inch and a half high at 100m and a inch an a half low at 200m it showed 2900fps.. Now if this is right i dont know as someone ran this load through his quickload program and said i would be getting about 2750fps. That was before i shot it and checked real world results though but i might be wrong in my calculations. It a .308 150gr SST with 46gr of varget that is shooting into one hole at 100 meter.

Gavin
 
Bob, Varget is very similar to Reloder 15. 46 grains should be giving you around 2800fps in that barrel, maybe a little less. In any case, it will be more than adequate for any deer walking these islands.
 
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Went for the 20" chop in the end through advice from members mainly CD, got it back monday night tried it yesterday.
What a difference really impressed with the cmm4 au mod ,think i made the right decision even at 20 " its still a longish rife with mod attached.
Its a couple of inches longer than my choped .243 with predator 8 compact, but a whole lot lighter you just dont know its there.
Thought the noise level was on par with the pred 8, recoil drastically reduced didn't think it made it more accurate with the reduced recoil but what i did notice you can see the target after the shot.
Well worth doing looking forward to using it this weekend on the munties . DF

Comparison with over barrel and muzzle can both 20"

View attachment 5334 View attachment 5335

...I like the look of that slimline mod!! (TBH, I like the look of both full rigs!!:D)

What's the going rate for one, if you don't mind my asking? (I've got a variation in for a .308 & mod at the moment......).

I've got a S/S PES on my .243: slimmer than T8's, etc, but not the lightest tube on the planet, it has to be said....
 
I spoke to South Yorks Guns (Rimfire Magic). They first cut my .22 CZ barrel back to 16" which actually increased the muzzle velocity as apparently that is the optimum length for my CZ. You can lose fps if the barrel is too long or too short. They are currently cutting my .223 down too. They do an excellent job there and know their stuff. Give them a call. If you get the barrel chopped and re-threaded at the same time it will save you money, rather than having to go back a second time.
Hope this helps :)
 
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