20BR Load Development Results

[garyw]

 

My rifle is now up to 700 rounds, I had it bore scoped yesterday and was told it is in very good condition with only minimal wear on the throat.

 

The gunsmith felt that the current wear in relation to the number of shots fired was very good and that the 20BR was far from a barrel burner.

thats good to hear AL.

[Alycidon]

I found I got more velocity from N150 than N550, I was expecting less. N150 is my go to powder on 20BR. Nice and cool, nice case full will give you 3300-3700 depending on the bullet.

 

A

[Raifuru]

 

Ive just bought myself a nice 20Tac, apparently the guy who sold it to me was spotted in a motorway services on the M6 last Saturday afternoon weeping into his coffee!

 

I will shoot this 20BR out first them maybe come down to Diggle and see what these bigger guys are all about

 

I'm using 50s and 55s in my 20 TAC and the results are definitely good. I am finding 2520, Varget and RL15 so far. I am trying VIT 133 & 140 at the weekend. So far 25.4 of Varget is the load that works best for both bullets. I also ran some 32s just to see if the fast barrel would be okay and results are good too.

[Big Al]

I'm using 50s and 55s in my 20 TAC and the results are definitely good. I am finding 2520, Varget and RL15 so far. I am trying VIT 133 & 140 at the weekend. So far 25.4 of Varget is the load that works best for both bullets. I also ran some 32s just to see if the fast barrel would be okay and results are good too.

 

21.5gr of N133 under a 55gr Berger works well in my 20Tac with a big jump of around 0.120" in a 9 twist.

 

Can I ask what your doing with your 55's?

[Raifuru]

 

21.5gr of N133 under a 55gr Berger works well in my 20Tac with a big jump of around 0.120" in a 9 twist.

 

Can I ask what your doing with your 55's?

 

 

21.5gr of N133 under a 55gr Berger works well in my 20Tac with a big jump of around 0.120" in a 9 twist.

 

Can I ask what your doing with your 55's?

How do you mean? I was intending on trying as small a case as possible that would reach 1000 yards. Still on the load development to see if it is feasible.

[Big Al]

 

How do you mean? I was intending on trying as small a case as possible that would reach 1000 yards. Still on the load development to see if it is feasible.

 

Im curious about your load data and seating depth you are getting these good results with on the 55's out of the 20TAC and also what twist barrel do you have?

[Raifuru]

Firstly I was wrong 25.1v has produced the best with the 55s thus far.

I have two load depths for the 55s they are 2.459 & 2.334 (if used in a magazine) 2.304 for the 50 (so far the most accurate bullet. The gun was originally a 75 built by Neil with a PAC NOR 1-11 (I believe). After a couple of years I decided to see what it could do at longer ranges and liked what the higher BC bullets looked like on paper. Dolphin put a Lija 1-9 on and it shoots anything.

I have used Todd Kindlers data to a point, but some loads were definitely too warm. I then decided to work up using medium powders like Varget and never got to the point where pressure seemed to be a problem at all. I have used 26 gains of 2520 and decided that was max. Quickload does not like any of my loads, but I use QL as a guide rather than a rule. My 270 WSM could not get close to the QL safe loads and even some yellow ones gave me problems.

I can post some of the groups I have achieved with the loads, but obviously would not suggest you use any of them without working up. All of the reloaded cases are nice and tight around the primer and never had any problems with sticky bolts with the loads I have quoted.

It is a real shame Berger stopped the 50s, but I managed to get a good supply before they were all gone.

 

I'll put some of the targets up on PB in a bit and will also put the Vit finding from Saturday up too.

 

 

 

 

http://s71.photobucket.com/user/greenersg/library/Darne?sort=3&page=1

 

Hope the links work. Warts and all photos I am afraid.

[Big Al]

I have two load depths for the 55s they are 2.459 & 2.334

 

How far would each of these be from the lands?

[Raifuru]

 

How far would each of these be from the lands?

They are on them with the exception of the magazine length load, but to be fair the accuracy does not seem to be far off using the deeper set bullets.

[Big Al]

I decided a few months ago to sell my 20BR as it just wasn't getting much use and my cabinet is full. I found that I use my 20Tac more as the 20" barrel makes it more handy from the truck window, the 26" barrel on the 20BR makes it more a roof/bonnet rifle. I advertised the 20BR here and elsewhere with almost no interest. I even decided that breaking it might be a good idea so I took it out yesterday evening for one last shot before implementing the plan of selling it in bits.

 

First shot was an easy crow at 285 yds then I set up a target at 300yds and fired one 3 shot group in still conditions, that was the first 4 shots from a clean bore. I put the rifle back in the slip and have decided what I really need most is a bigger cabinet!

 

#nolongerforsale #boysandtheirtoys!

 

 

 

[Big Al]

So if yesterday wasn't enough - half a dozen rabbits this afternoon at what I consider long ranges put a smile on my face, the best one being 560yds.

[Raifuru]

I decided a few months ago to sell my 20BR as it just wasn't getting much use and my cabinet is full. I found that I use my 20Tac more as the 20" barrel makes it more handy from the truck window, the 26" barrel on the 20BR makes it more a roof/bonnet rifle. I advertised the 20BR here and elsewhere with almost no interest. I even decided that breaking it might be a good idea so I took it out yesterday evening for one last shot before implementing the plan of selling it in bits.

 

First shot was an easy crow at 285 yds then I set up a target at 300yds and fired one 3 shot group in still conditions, that was the first 4 shots from a clean bore. I put the rifle back in the slip and have decided what I really need most is a bigger cabinet!

 

#nolongerforsale #boysandtheirtoys!

 

 

 

300 Yards......That really is excellent. I would not expect anything like that from the 20 TAC. I certainly would not get rid of it.

[stephentri]

Hi what's the 55grain bergers like on vermint do they pencil through or fragment like a vmax.

[Big Al]

Hi what's the 55grain bergers like on vermint do they pencil through or fragment like a vmax.

 

Both!

 

At 560yds it drilled a hole through the rabbit but because it was a chest shot it was dead instantly, sub 400yds they do fragment well though, I think you need to choose your application wisely.

 

I have reservations on using them at distances over 400yds on rabbits after Sunday but since my main target is crows then Im much less concerned because a hit anywhere will be fatal at any distance, I dont like the idea of leaving a gut shot rabbit to die slowly. So far the ones Ive shot to 350yds range have been devastated with violent expansion similar to vmax.

[gbal]

As Al says,(long range) varminters have to consider ethical (ie instantly fatal) terminal performance of bullets. There will always be a few exceptions,sometimes due to hit location,but terminal performance is mainly determined by bullet construction (eg jacket thickness) and velocity.

Choice of bullet should take the match between size of quarry (and construction thereof!) and the design suitability into account -remember most are designed for US varmints- as much as accuracy.

This issue is critical for larger game,and we can learn a bit from eg Nathan Foster's ideas-he classes bullets by their lower limit terminal velocity effectiveness-ie he determines when velocity has dropped so much that bullet performance becomes unreliable,and that defines maximum range for that bullet (range,since bullet velocity relates to range in predictabe ways,when BC and MV are known.

 

While less critical for much UK varminting,the idea serves to emphasise correct bullet selection,and will help avoid pencil through terminal (non) performance on species where this is considered undesireable. (all really,but imaybe it's good enough on corvids?)

I suspect the sometimes variable reports of longer range shots may be due to terminal velocities getting too low in some cartridges/barrel lengths....

...and no,alas,there isn't a coherent analysis of bullets/velocities yet for UK species-but user reports help a lot. Photos are not necessary-it's a PR thing. It also has some bearing on edibility,where applicable.

 

gbal

[Big Al]

I managed to get out with my 20BR again on Sunday, conditions were almost identical to last weekend and results were again very encouraging. Sunday was all about targets but on the way we stopped the jeep while I took on a crow at 317yds with a clean cold barrel, the shot was successful at at those ranges the 55gr Bergers open up nicely with devastating results.

 

My friend shot a few groups at 300yds with his .223 then I fired one 3 shot group at 300yds, I was hoping to get it out to 600 but time beat us. I was very happy to see the consistency from my group last weekend with an almost identical POI but also a little confused. After dropping just over 3/4" low last weekend with 9 clicks of elevation I gave this one 10 clicks which should have brought me up to the centre but again the group fell just under 3/4" low. The slight impact left would suggest I need to adjust my zero by one click to the right as both groups were shot in what I consider wind free circumstances and two entirely different locations.

 

Im really starting to like this rifle.

[Big Al]

Guys,

 

As a result of another discussion Ive just taken a look at my seating depth for this load, I knew the bullets were jumping a good way but not quite as much as they are. At present they are jumping 0.153" - thats just short of 4mm. Has anyone else had good accurate results with jumps this big?

 

The long one is touching the lands, the short on is how they are loaded. As things stand the boat tail/bearing surface junction is level with the case neck/shoulder junction and the whole bearing surface is supported by the entire case neck rather than floating in fresh air as in the longer seated one.

 

I wonder if this has anything to do with my good accuracy?

[mtb]

Hi al

I load my 6br exactly the same way with 75 gr vmax 150 thou jump the accuracy is excellent

rgds mike

[Big Al]

Hi al

I load my 6br exactly the same way with 75 gr vmax 150 thou jump the accuracy is excellent

rgds mike

 

Thats interesting Mike, especially since the 75 is quite short for caliber compared to the Bergers in mine.

 

How did you arrive at such a jump? did you start much nearer to the lands and work your way out or did you know something I didn't?

[gunner]

Al have you got a concentricty gauge ? As id be tempted to cheak the long ones before & after chambering with the concentricty gauge , and you must be right on the accuracy of the shorter ones , i bet there straighter than the long loads !

[Big Al]

Al have you got a concentricty gauge ? As id be tempted to cheak the long ones before & after chambering with the concentricty gauge , and you must be right on the accuracy of the shorter ones , i bet there straighter than the long loads !

 

That would make a lot of sense Gunner and was really the point I was trying to make earlier. I dont have a concentricity gauge at present and to be honest I dont think my OCW would let me sleep at night if measured everything that closely.