Scooby-93

4 hours ago, Catch-22 said:

Nearly 3000fps with a 142SMK from a 26” barrel! That does sound awfully high.

I know Viht data is very anaemic but that’s way off the chart. I guess a very long throat, thus seated well out of the case, may help. 

46gr with 147Eld was 2960 in mine not seated to long, still fitted in standard ai mag length 

7 hours ago, No i deer said:

I will try later to see how many grains of N160 the 47 case will hold up to the neck junction..

41.5grs of RS62 is up about that far and is a compressed load.

Have you tried RS62 and what was your max load..?

 

 Nope sorry only n160, charge weight test went up to  46gr before hitting pressure  (maybe over can’t remember) 

I have a friend shooting 130gr in his 47 with n160 and he is getting around 2900 with a low charge weight 

@No i deer

I am running 44.7gr of n160 for 2860fps with 147 eld in my creedmoor 

22 hours ago, baldie said:

Vhit 160/142 SMK at 2985 fps. Verified on Magneto speed and Labradar.

Small primer lap brass with small diameter pin in AXMC

26" Sassen cut barrel.

Nice cool powder, with no perceivable wear in the throat at 600 rounds.

Wont be bothering with 555.....

What is the charge weight Dave? 

1 hour ago, One on top of two said:

RS 62 = better results , more FPS , no need to compress loads , Cooler too .... oh and no need to use the girlfriends/ wife’s / boyfriends dildo either 

42 grains RS 62 = 2820 FPS with 24 “ barrel. 
no pressure signs at all . 
 

say after me ... Viht is 5hit . 

With which bullet?

1 hour ago, Alycidon said:

28 inch Bartlein, 1 in 9, so hardly ideal, 1 in 11 would have been better but the rifle was built around the 50gr Berger.        I went to around 4100 with the 39,   no need to go any faster,   but was getting pressure signs at that.  Have also been to about 3900 with the 50 Berger, match and varmint,    they also held together fine.

I would suggest as a working load 3300/3600 will be where you will find best accuracy,   given a heavy rifle ( mine is 14lb)  and no mod you should be able to see the bullets arrival.  I shot a crow with it some weeks ago at about 160 yards,  it dropped off the top of a drinking trough before I had registered the gun had fired.  If you are going 20BR then I would advise using N150 and either BR4s and Fed 205s,  that gives you a nice case full so a close velocity spread.

Dont forget barrel life is around 1500 rounds at sensible pressure and velocity,  you start pushing the limits and this will drop down to around 600 rounds,  thats a pound a round plus just for barrel life.

You will find it beneficial to weigh and batch your bullets by weight, use your powder scale.   Bergers are pretty good,  I once had 200 x 50s,    ALL were 50.0 or 50.1 which is remarkable.      I usually find in SBKs a spread of plus or minus 1 grain with the bulk falling into two or three weights.  For a pest control bullet thats perfectly acceptable.  

 

A

 

Thanks for the informative reply, it’s going to be a 20-250 and 10twist at 26” long. 
 

I will be using n550 and hoping to get 4200+ with around 38gr of powder.

barrel life will be low, Most likely sub 1000 but for flat trajectory to 300-400 yard it is more or less point and shoot give or take.

what charge we’re you getting 4100 with? 
 
The BR case will be a lot more efficient than the 20-250 but i needed a reliable  Feeding round from my tikka action so went with that instead 

20 hours ago, Alycidon said:

Data on 223 and N120 is available free here:

https://www.vihtavuori.com/reloading-data/rifle-reloading/?cartridge=7

Personally I would have said N120 is a bit fast for the caliber but you should be able to get away with in on the 40 gr VMax,

For the 50s etc I would deffo look for something slower like N133.   

Ideally you want a pretty full case,  (95% or so),  that way you get a uniform velocity, so a closer shot to shot velocity and thus a smaller group with less vertical dispersion. 

I would also recommend a look at Sierra Blitzking,   I use the 20 caliber 39s in a 20BR and 1 in 9,    hell of a good bullet,  holds together at over 4000 unlike the 40gr VMax.   But best accuracy as is often the case is way below top speed,  in my case about 3600.  

A

What speed did you push the 39 sbk up to? 
what length barrel, powder and charge also if you don’t mind sharing? 
I am hoping to get 4200+ out of them providing the accuracy is there at that velocity.

Avoid the 75eldm I know a couple people who struggled to get them to shoot consistently, 77tmk is a much better choice and especially on vermin 

PM’d you chicken tikka 

Do it, you won’t be disappointed!

75gr bullets at 3500fps with 24” barrel

iF you were to go 28” barrel I bet the 75gr would do 3600+

5 minutes ago, palo said:

That's good.  

My mate is using one of the new Mdt 6mmbr mags in his Remmy action 6mmbr rifle and it feeds well so they should be ok for the 20br as well 

That sounds promising 👍🏻 I think they only do a 12 round mag shame it wasn’t a 5 but it could be a option 

13 minutes ago, palo said:

The 55 grain Berger bullet is discontinued.  

There is still plenty stock in the uk to keep me going, certainly enough to last the barrel life 

Hi Justin, 

is this with a t3 action and is that 1 of daves converted mags or another smiths?

Hi all,

I’m looking at a high capacity 20 cal, in particular the 20br.

i have a tikka T3 to use as a donor, has anyone gone this root and had reliable feeding from the mag?

alternatively I am thinking 20-250 or 20x47.

i think the 20-250 will be easier than the 20x47 in making brass but I like the idea of the small primer in the 47 case.

anyone with any of these calibres could you please share your experiences 

Im wanting to shoot the 55gr Berger 

Literally same hole groups with 3 Different loads/bullet he has had developed. 

it’s his main gun for vermin control.

22 creedmoor 3500+ FPS with a 24” barrel and 75gr bullets 

my friend went the opposite to you, he went from a 6x47 to the 22 creedmoor and hasn’t looked back 

2860 FPS with 44.6gr n160 under 147 eld 28” barrel though

My creedmoor is doing 2866 fps with 147 eldm using viht n160, but I do have a long barrel so I’m assuming that’s contributing to the speed.

so it all depends on the spec of the build as to get the most of out the cartridge 

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