Advice for new 20 caliber project shooting 50 grains

[londonhunter]

Hi guys I would like to go ahead with a new varmint rig in 20 tactical.

 

Just wondering has anybody any success with the new berger 50 grain pills down a 1 in 9 twist tube ?

 

So far all the people I spoke to with experience in the 20 tactical are all shooting 1 in 10 or 11 stabilising 39 / 40 grains

 

It mainly for foxing and paper punching.

 

My thinking behind thos project is that the 50 grain will be more stable in the wind and less recoil as compared to a 6mm.

 

However my gunsmith is trying to discourage me saying that 20 caliber are best spinning 39 / 40 grainer with the case size.

 

Is this comment accurate from your experience ?

 

Thanks

[20ppc]

Hi guys I would like to go ahead with a new varmint rig in 20 tactical.

 

Just wondering has anybody any success with the new berger 50 grain pills down a 1 in 9 twist tube ?

 

So far everybody who knows somebody with experience in the 20 tactical are all shooting 1 in 10 or 11 shooting 39 / 40

 

It mainly foxing and paper punching weight is not a issue.

 

My intention is that the 50 grain will be more stable and not get blown about in the wind and not much recoil as compared to a 6mm

 

thanks

 

 

Hi Benjamin,

 

If you are set on using 50gr bullets I would suggest that you go for either a 20ppc or preferably a 20br or even 20x47. The Tac 20 is a little underpowered for th 50s. I know Bruce Potts has had excellent results with the 50s in a 1in9 twist 20x47. Having said that I have had excellent sucess with 39gr blitzkings in my 20ppc in all sorts of conditions,

 

If you want to shoot the heavier bullets go for a bigger case capacity.

 

All the best,

 

Nick.

[AHPP]

There's a natty little table somewhere in internet land; a column of bullet weights and corresponding column of appropriate .20 cartridge. BR is supposedly best for the 50s with the PPC close behind. I'll see if I can lay my hands on the table.

[Alycidon]

Hi,

 

I am in the early stages of load development with my 20BR, this is a 1 in 9 and throated for the Berger 50 gr bullet.

 

Quickload suggested that N150 would be the powder of choice on a pressure/case fill/velocity basis but as per usual it has not quite worked out like that. My initial 34 cases loaded from 28.0 to 31.5gr showed a preference for the lighter loads, these shot into the .2s when I did my bit, .4s when I did not. Primers (fed205s) start to show slight cratering at 30.5gr. Velocity at 29.0 is around 3450fps with an ES of 15. None of the groups went beyond .7 and all loads shot to the same point of aim. 32.5gr x N150 takes it to 3800 but I am getting .00035 to .0005 expansion at the base as well as severe cratering. Barrel life at 28gr is about 30% longer than at 32gr, drops at 300 yards are again not to far different, a few clicks.

 

The bullet is excellent, weights are outstandingly precise, in my last batch of 200 ALL weighed either 49.9gr or 50.0 gr. The few 40gr Vmax I have so far weighed are also far better than anything I have ever measured in 6mm weight variation wise.

 

Thanks to Vermincinerator and Menial 1 I have borrowed from each of them a drop of N550 and N160 respectivly. I have loaded 10x N550 cases with 28.0, 29.5. 31.5 & 33 gr, I intend to load 10x N160 with weights from 30.0 up to around 34gr. The idea is to see if a larger load of a slower powder will produce better velocities at the same or lower pressures. Hope to shoot them shortly.

 

Having failed dismally to get hold of some 39gr Blitzkings from Norman Clark last Saturday I have now loaded some 40gr vmax that he had got with light loads of H322. I expect about 3700 fps from them when worked up to same pressure levels, pretty low I know but fast enough for what I want.

 

I would agree the 20Tac and 20 Prac are best suited to the 30 to 40 grain bullets, Greg Tannell the well known US custom smith reports in Todd Kindlers book that the 33gr Vmax is doing 4350fps and shooting in the .3 & .4s in a 1 in 13 Pac Nor 3 groove at 26.5 inches finished.

 

My BR is a big heavy rifle, over 14lbs with a laminated BR type stock on it, recoil is practically non existant and hits are easily seen even without a mod fitted. Barrel length is 27". I also shoot a lighter moddied 6PPC, 65gr Vmax leaves at about 3300, trajectories out to 300 yards are not that different to the downloaded BR.

 

Todd Kindlers view is that the 50gr is best matched to the BR case. It is generally accepted that the 1 in 9 twist you do need for the 50s will also shoot the lighter bullets well. Some US guys are saying that the faster twist which yields a faster spin rate causes more splatter effect on small targets such as crows, rabbits etc when using vmax etc.

 

Typical 50gr fox kills are no mark on entry other than a slight blood spot and a decent exit wound, not as good as a 6mm 65gr Vmax usually is but no fox I have shot with it has asked for another.

 

I think you have a choice, if you do 20Tac or Prac20 and fire the 50gr you will struggle to get it past 3200fps, even then you will be using a full case and compromising barrel life. So if its the case you like then really the 33gr Vmax flies and the 39gr BK is a good all round bullet, more accurate than the 40gr vmax in most rifles I have read about. If you want to use that bullet then have some more case capacity under it.

 

Have a look at the ballistics here,

http://www.biggameinfo.com/BalCalc.aspx

 

bullet BCs are available from the manufacturers web sites, the Berger 50 is .281 from memory, they have just reduced it a shade.

 

A

[londonhunter]

OK last question if I put th question another way. I am commited now with 1 in 9 twist and 223 bolt face.

 

I know it will stabilise 50 grain around 3200 fps or thereabout.

 

Will this setup stabilise 40 grain ?

 

i.e. Do I have the option of going backwards in weight ?

 

thanks

[menial 1]

I shot 39grn blitzking into the .3's in my 1in8 tubed AR in .223 over 24.5 of vv133 with no load development. Your .20 should have a slightly greater bearing surface over .224 bullets so shouldn't really be a problem, you'll know when you try some.

Pete.

[Alycidon]

OK last question if I put th question another way. I am commited now with 1 in 9 twist and 223 bolt face.

 

I know it will stabilise 50 grain around 3200 fps or thereabout.

 

Will this setup stabilise 40 grain ?

 

i.e. Do I have the option of going backwards in weight ?

 

thanks

 

 

Normally yes according to the US sites but I am having issues with it at present which I suspect is down to seating depth but might be the spin rate is causing them to break up in the air. I am pretty sure that at my 26.0gr x H322 is a good load, See my 20BR load development thread for more detail.

http://ukvarminting.com/forums/index.php?showtopic=6301.

 

A.

[menial 1]

40grn bullets are being sent at over 4000fps in 22-250 and 220 Swift and not breaking up, why should they be anymore prone to breaking because of spin rate in .20 cal which will probably max out at 3900fps with 40grn bullets. I've not met anyone in the UK who has had bullets break up through over spinning.

Pete.

[Alycidon]

I hear what you are saying and vermincinerator saw no tell tale evidence of a mid flight break up BUT 3 bullets all went missing totally in a load of 27.5gr from memory, around 3600. No marks on the card at all and at least 4 inches each side of the target dot. Gun then shot a group of .4 ish at 200 yards with 50s.

 

Must be the twist (1in9) rate, surely the swift etc are a slower twist.

 

A

[menial 1]

My 1in8 spits 40's out at over 3500fps and that has included TNT's. Bullet construction has come on in leaps and bounds in recent decades and bullet break ups with normal loads seems to have been consigned to the history books.

Fast twist rates tend to generally reduce mv and reduce the spin/break up problem to a certain extent. Perhaps you're shooting screamers Geoff and some of the shots are being lost down the same hole.

Pete.

[Vermincinerator]

40grn bullets are being sent at over 4000fps in 22-250 and 220 Swift and not breaking up, why should they be anymore prone to breaking because of spin rate in .20 cal which will probably max out at 3900fps with 40grn bullets. I've not met anyone in the UK who has had bullets break up through over spinning.

Pete.

 

40grn bullets coming out of a 1-9 twist 20 calibre barrel at 3900fps are spinning considerably faster then the same weight of bullet out of a 1-14 twist 22-250 at 4000fps.

I fire 52grn bullets out of my 22-250 AI at 4050fps and out of my 1-14 twist barrel the spin rate is just over 200,000rpm

Geoffs rpm is approaching 300,000 revolutions the area where bullets start to break up, however like Geoff said i did not see any signs of vapourising bullets.

I have had first hand experience of this when 70grn SMKs exploded into grey puffs of smoke 30-35yds in front of the muzzle when pushed hard out of my 1-9 twist 243 AI.

 

Ian.

[menial 1]

Perhaps I've got a new experience to look forward to when I start stoking up some lightweights in my 1in9 twist .243AI I've just had put together.

I do understand faster twist rates equate to more bullet spin, but as I said, with normal powder loads the problem is unlikely to occur.

I never close my mind to other peoples opinions Ian, only fools think they can know better than everyone else.

Pete.

[Vermincinerator]

As you know Pete, i like to push the envelope a bit mate, i have no idea how fast the matchkings were going because they did not show up on the chrony.

Its all a bit of fun seeing how far things can be pushed but the down side is huge amounts of copper fouling and hours of labourious cleaning to restore accuracy.

I have had my fill of the fast stuff now, i am leaning back towards accuracy rather then speed, having said that my .257 AI is a wonderfully balanced accurate shooter.

When funds will allow i shall be re-barrelling the 22-250 AI to fast twist 22BR.

 

Ian.