20BR load development

[Alycidon]

Yesterday Vemincinerator and I went and had a play with a number of experimental loads using N550 and N160 that has been loaned by Vermincinerator and Menial 1 with thanks.

 

N150 is the theoretical powder of choice but I get cratering start at 3500 approx with the Berger 50gr. Yesterday I tried some N550 and N160 loads, my thoughts were a bigger dose of a slower powder may give us a more delayed velocity spike and lower pressure while retaining good velocity.

 

Powder Charge velocity Groupsize (inches) Comments

N150 28.0 3318 .52 Best of 2 groups

N150 28.5 3365 1.18 ES38

N150 29.0 3441 .80 ES20

 

N550 30.0 3434 .55 ( 3 of each only loaded as powder borrowed)

N550 31.5 3549 1.40 ES9

N550 33.0 3680 1.00 2 in 1 hole, slight cratering. need to lower .3gr

 

N160 32.0 3416 .42 see note (2 of each loaded only as powder borrowed)

N160 33.0 3430

N160 33.5 3510 ES3

 

The N160 targets have been hit with wild 40gr Vmax bullets making accurate assesment impossable but 32.0 & 33.0 shot around a .5 group. 33.5 was 1.25, horizonatal spread.

 

You can see that in all cases the lighest load is the more accurate one.

 

We then moved on to trying some 40gr Vmax over some H322. In short accuracy wise they were a disaster. Some even not appearing to trouble that target backer, back to 100 yards and N150 with them, set a bit deeper into the case.

 

40gr Vmax, H322

 

26.0 3507 ES34 Nice load on the shoulder, could be a .7 group

26.5 3582 ES18

27.0 3598 ES4

28.0 3752 ONE SHOT ONLY Mild cratering, top load pressure wise.

 

Heaveir H322 loads to be pulled.

 

So at the moment loads of 28.0-29.5 gr N150 are worthy of further investigation.

 

These loads are shot in my rifle and not warrented for any other rifle, start low, work up etc.

 

A

[Vermincinerator]

IMO proper load evaluation cannot be undertaken without a good chrony, there were some very low spreads produced by some of Geoffs loads, showing a good consistant loading technique and efficiency of the BR case.

Range by the way was 200yds

My 257 AI was spitting out the 85grn BT's at an average of 3340fps and grouping about 1 1/4", not bad considering i have not done any load developement.

 

Ian.

[bigun]

what primers did you use ?? did you try only the one type ?

[Alycidon]

At the moment I have stuck with Fed 205 match, I do have some BR4s and will load some under the light loaded 50s in the next batch I do. I know that 28-29.5 N150 shoots well with 205s so lets see what BR4s will do. I suspect they will be slower.

 

That chart is quite excellent, I have a N550 group like the top left one and a couple like the lower left. Where did you find it?.

 

 

A

[bigun]

i made the chart my self and had it checked by a guy who knows his stuff and he says im right good to look at when you may be pulling your hair out ..id try the br4 primers i love them or should i say my rifles do ..iv found that if i find the bullet is hitting the mark and you go up in powder i find that it will go off the poa and then back on again once i get to about the xtra 2gn mark .as you know you have to go up slowley just to find the sweet spot ,but remember some bullets dont like some barrels and some powders dont like some bullets ,each bullet likes to go to a rpm you just have to find it ,short bullets like slow twist barrels and long bullets like fast twist barrels .eg mate has a 22-250 1-14 twist barrel shoots the 55gn gamekings very well indeed but after playing with the 40gn vmaxs bullets id say it shoots them far better and with better results at the end of its path ,mind you they are doing over 4,000fps and its just what you need for a varmit rig great fun to watch

 

 

 

50Berger LTB VV N540 32.8 Fed 205m 3800fps Lilja 1:9

 

40 Hornady Vihtavuori N-550 33.5 Max 4010fps 24.0" barrel

[Alycidon]

i made the chart my self and had it checked by a guy who knows his stuff and he says im right good to look at when you may be pulling your hair out ..id try the br4 primers i love them or should i say my rifles do ..iv found that if i find the bullet is hitting the mark and you go up in powder i find that it will go off the poa and then back on again once i get to about the xtra 2gn mark .as you know you have to go up slowley just to find the sweet spot ,but remember some bullets dont like some barrels and some powders dont like some bullets ,each bullet likes to go to a rpm you just have to find it ,short bullets like slow twist barrels and long bullets like fast twist barrels .eg mate has a 22-250 1-14 twist barrel shoots the 55gn gamekings very well indeed but after playing with the 40gn vmaxs bullets id say it shoots them far better and with better results at the end of its path ,mind you they are doing over 4,000fps and its just what you need for a varmit rig great fun to watch

 

 

 

50Berger LTB VV N540 32.8 Fed 205m 3800fps Lilja 1:9

 

40 Hornady Vihtavuori N-550 33.5 Max 4010fps 24.0" barrel

 

 

Are these loads in 22.250 or 20BR ?

 

I can emulate the upper load in the 20BR with N150 (32.0 from memory) but get severe cratering and case web expansion of about .0005 even though I have another 3 inches of barrell.

 

A

[bigun]

theses are for the 20br ccibr4 primers have thicker cups so are far better if your pushing that bullet that little bit harder ..

 

50Berger LTB VV N540 32.8 Fed 205m 3800fps Lilja 1:9

 

40 Hornady Vihtavuori N-550 33.5 Max 4010fps 24.0" barrel

[Alycidon]

Are they now, that might be a help indeed, thanks for that..

 

It will be interesting to see what 31.0 of N150 will through a longer barrel but I have to watch the web expansion as these cases have a lot of work in them. That VMAX load looks a cracker, dynamite on rabbits etc.

 

What velocity area does yours produce best accuracy with the Berger 50?. How did you find velocity variations using the same load with 205s and BR4s?. I expected the BR4s to be slower as they are a cooler primer.

 

A

[bigun]

the loads that i gave you were off this site ammoguide.com .pay under £14 and you have full use of the site ..i think its a cracking site ..useing slow burning powders means your barrel will get hotter faster than useing a fast burning powder ..so im told, which means what ?, less shots on the day plus waiting for the barrel to cool down ,which is a bore ..just thought id let you know that .if you get no real joy useing the 50gn id try a lighter bullet which in my mind is what a .20 should be shooting ,good for out to 500mtrs which is a long way for such i little bullet mind you saying all that i know your after a bullet with less wind drift, a 32gn say at 400yrds and a 6mph wind will drift about 10.6" as a 39gn bullet will drift 10.0"becouse the 39gn is only doing about 3600fps were the 32gn is doing 4150fps ..so what ever you use get it moveing to beat the wind

[Alycidon]

the loads that i gave you were off this site ammoguide.com .pay under £14 and you have full use of the site ..i think its a cracking site ..useing slow burning powders means your barrel will get hotter faster than useing a fast burning powder ..so im told, which means what ?, less shots on the day plus waiting for the barrel to cool down ,which is a bore ..just thought id let you know that .if you get no real joy useing the 50gn id try a lighter bullet which in my mind is what a .20 should be shooting ,good for out to 500mtrs which is a long way for such i little bullet mind you saying all that i know your after a bullet with less wind drift, a 32gn say at 400yrds and a 6mph wind will drift about 10.6" as a 39gn bullet will drift 10.0"becouse the 39gn is only doing about 3600fps were the 32gn is doing 4150fps ..so what ever you use get it moveing to beat the wind

 

 

The 50 shoots in teh .2s at velocities from 3300 to 3450 so it does work OK. Berger brought the 50 out for the BR and 20.250 case, the Americans are using them to 800 yards when they start to get tired, the 39/40s are only good for 600 and best suited to the TAC20/PPC case. But in a BR they can really shift !!.

 

At the rate I get through ammo unless testing then barrel heat is not an issue, I did put a link up to barrell wear rates a few weeks ago, http://accurateshooter.net/Blog/barrellifeupdate.xls

 

That says the hotter the powder the faster the wear, I dont suppose we use enough ammo to know who is right.

 

I did have a look at Ammoguide on a free day maybr a year ago. They only had 3 loads for 20BR at the time from memor, looks like things have changed. I was speaking via e mail to Walt Berger the other week on 20Br loads and he is putting some info together.

 

A

[bigun]

thanks for the link i shall read it in side out im sure you will find a load as i hear the br is not to fussy unlike some rifles around ..i know the .20 will reach out to 600mtrs iv done it but only on target ie a 5" stone in a strong wind ,so 800mtrs? i have no dought it will do it ..im well happy with the rifle i shoot but like you i want more or should i say the best in that cal ,and was told the br20 is the one to go for ,so i read your posts with open ears as one day soon i will also be having one as i think the .20 is one of the better varmit rounds about .whats not to like about it .

 

i got given this round the other day ,in the pic below its a .20 thought you may like to see it .204 ruger case on the right

 

 

[Alycidon]

The 6x47 case has a capacity of around 47 grains. the BR case maybe 35 or 36 and in a 20 you dont go to capacity normally. 32gr N150 gets the 50 to 3800 but at a cost.

 

It does look a nice cartridge but it burns 50% more powder than my N150 loaded cartridge doing 3500 fps, that makes mincemeat of your barrel life. You would really need a much heavier bullet to make best use of that capacity, 6x47 was I think designed around about a 120 grain bullet.

 

I really cannot see any advantage at all in a case bigger than the standard BR case with the bullet weights we have available at present. I thought about Ackley ing the case to lower the pressures or even a 20 Dasher but I was advised that gains were minimal. Todd Kindler strongly advised me to stay with the standard BR case. So I will try the BR4s that you recommended and see where we go from there.

 

All my live shooting is sub 300 yards, I do sometimes shoot targets further out but for what I do it seems fine at present.

 

A

[Andrew]

IMO proper load evaluation cannot be undertaken without a good chrony, there were some very low spreads produced by some of Geoffs loads, showing a good consistant loading technique and efficiency of the BR case.

Range by the way was 200yds

My 257 AI was spitting out the 85grn BT's at an average of 3340fps and grouping about 1 1/4", not bad considering i have not done any load developement.

 

Ian.

 

I couldn't agree more. Additionally, for those willing to give up the price of decent optics, there is the "Pressure Trace" unit that I bought. It will measure direct chamber pressure via a piezo-electric sensor mounted to the barrel ahead of the receiver and run through a lap-top/ software. It will not only show chamber pressures but rebound spikes in pressure throughout the pressure curve generated by a given round. I don't use it much as the sensors are $90 USD each and must be epoxied the rifle in question, but it certainly gives you the absolute truth about your load. Cratered or rounded primers don't always tell the story! Many a "good" load was found to be running "hot" when the actual chamber pressure was measured. ~Andrew

[Alycidon]

I couldn't agree more. Additionally, for those willing to give up the price of decent optics, there is the "Pressure Trace" unit that I bought. It will measure direct chamber pressure via a piezo-electric sensor mounted to the barrel ahead of the receiver and run through a lap-top/ software. It will not only show chamber pressures but rebound spikes in pressure throughout the pressure curve generated by a given round. I don't use it much as the sensors are $90 USD each and must be epoxied the rifle in question, but it certainly gives you the absolute truth about your load. Cratered or rounded primers don't always tell the story! Many a "good" load was found to be running "hot" when the actual chamber pressure was measured. ~Andrew

 

 

Cant say I fancy sticking sensors on with Araldite or similar, I will just watch the primers thanks.

 

I do take your comments on board about safe loads maybe cratering, my PPC craters at 29.5gr x N133, not badly but it still does. The load is what was recommended by the builder and it shoots well. I know some of the US BR guys are into even more powder and compressed loads. I did run this down to 27.0 but the groups opened up, the harder I drive it the tighter it shoots, usually!.

 

I knew I had seen that 20x47 case before, its the 20 Satan designed by Bruce Potts, cant see much on it though but I know that Bruce wrote an artical on it a few years ago, got anything to share on it?.

 

A

[Alycidon]

Earlier this week I had a play with BR4s, wind was over 20mph so accuracy was not that hot but I saw no pressure signs at all. Best group with the 50gr Berger was a .4 with 31.0gr N150, that is cratering with 205s. Once we get some still weather I will chrono the load but the load shows good potential.

 

The 40 gr Vmax over N150 this time are impacting around .5moa higher than the Berger 50s at about 120 yards but they are at least now all arriving intact. Most accurate load was 29.5gr x N150 with 205s that clover leafed. That is looking like my crow buster.

 

Loads are not warrented in your rifle but are safe in mine.

 

 

Got it just past 200 yards last night on a crafty old vixen, that for me is a long way at night. My Disco is going so I have moved my electrical connections to a Defender.

 

Only 10 seconds after I started and 40 yards down my current red hot field outside our house an eye reflected back on the top of a hill. As that switch failure cost me a cub there the night before I was tooled up ready. Couple of flashes then she's off down the bank onto my range area. She stopped, turned to face me for a quick look at this green thing, I knew the range was around 200 yards as she was close to a tall sycamore but she was down a steepish bank. Held a shade low but still on her lower front chest, seemed ages before the thump came back. No moddy on this one. Bullet (Berger 50 MEF varmint) did not expand, in front chest out in front of rear leg with minimal damage. Old vixen, had been wet but now dried up, mother of some these cubs I have been having I recon. Thats 7 from this field now in 6 weeks and only 5 from the other 1000 plus acres, go figure. I recon they like the sheep crap.

 

A

[Ballistic Hamster]

Cant say I fancy sticking sensors on with Araldite or similar, I will just watch the primers thanks.

 

I do take your comments on board about safe loads maybe cratering, my PPC craters at 29.5gr x N133, not badly but it still does. The load is what was recommended by the builder and it shoots well. I know some of the US BR guys are into even more powder and compressed loads. I did run this down to 27.0 but the groups opened up, the harder I drive it the tighter it shoots, usually!.

 

I knew I had seen that 20x47 case before, its the 20 Satan designed by Bruce Potts, cant see much on it though but I know that Bruce wrote an artical on it a few years ago, got anything to share on it?.

 

A

Hi had a satan built by steve bowers barrel life not 700 rounds pushin out 50 grain burgers at 4000fps so expensive play did some bunnies 800yds might have load data somewhere if you want it

[Alycidon]

I think the members may be interested anyway so please post it, perhaps on a Satan thread then if others are looking for Satan in a search it should come up. Info on the most accurate load would also be appreciated. Usually best accuracy is some way below max velocity.

 

Not had any time at all to do any further work with my BR. Only shot a couple of foxes with it in the last month. Need too load some first though, looks like BR4 primers may be the way to go with loads over 31.0gr, just need to mic the fired cases.

 

But the benifits of the 40gr Vmax over the 50gr Berger are only in explosive impact on crows. Ballistically sub 250 yards they are more or less the same although 120 yard impacts are .5moa apart. I wont be buying any more but might try a few 39gr SBKs at some point.

 

A