20 BR Powder Choice/Load Data

[AnthonyR]

My 20 BR is a few weeks away and I am looking to get the rest of what I need to start loading for it, which in reality means powder choice as I think I have everything else.

Rifle is a 10 twist with a 233 neck.

I am planning on using the 39gr Sierra Blitz King bullet and I am looking for a powder that will hopefully get me somewhere up near 4,000 fps.

I have RL10X, CFE223, RL15, N140 and RL17 here already and would rather use one of these but happy to get something else if required.

Anybody got any loads and experience they are willing to share??

[treecutter]

39g SBK, 30.5g Viht N133, CCI BR4 primers, Lapua 6br brass 3950fps

Sassen 1:10 twenty four inch barrel fitted by Baldie Dave on here.

I went for N133 as apposed to RL10x as its slightly kinder to the barrel.

Never mind the lock time, the bullet seems to arrive before you've finished pulling the trigger!  you are going enjoy yours....

[AnthonyR]

Thanks for that, that’s exactly the info I was after!

I have been using RL10X in my 20Tac for years, that rifle has now fired over 4500 rounds and the accuracy has only really started dropping off in the last few hundred rounds so it can’t be that bad surely!!!

 

[treecutter]

I used RL10x in my .204 to good effect but as its a double based powder and the 20br is an overbore cartridge I went with a single based powder.

[OSOK]

I ran a 20BR with 50g Bergers for several years and used 32.5g of N550 and a Fed 205m which gave me approx 3,700 ft/sec

OSOK

[KABOOM]

On 9/6/2020 at 11:07 AM, AnthonyR said:

Thanks for that, that’s exactly the info I was after!

I have been using RL10X in my 20Tac for years, that rifle has now fired over 4500 rounds and the accuracy has only really started dropping off in the last few hundred rounds so it can’t be that bad surely!!!

 

Yes I have 4200 through a 22-250 RL15 and IMR8208XBR shoots fine just not quite as fast. Imo lots of the barrel burnout talk is over stated. each use ie bench rest has its needs but for vermin it really don't matter. The 1k yard shooters have another standard Im sure.

 

[Scooby-93]

On 9/5/2020 at 7:00 PM, AnthonyR said:

My 20 BR is a few weeks away and I am looking to get the rest of what I need to start loading for it, which in reality means powder choice as I think I have everything else.

Rifle is a 10 twist with a 233 neck.

I am planning on using the 39gr Sierra Blitz King bullet and I am looking for a powder that will hopefully get me somewhere up near 4,000 fps.

I have RL10X, CFE223, RL15, N140 and RL17 here already and would rather use one of these but happy to get something else if required.

Anybody got any loads and experience they are willing to share??

Out of your powders I would try RL15 or N140 first, failing that I would buy N135 

[AnthonyR]

I actually ended up buying some N133 as somebody else not on here gave me some load data as well for that.

However I am not getting anything like the sort of velocities I am hoping for, still only fire forming the brass but I can't even get to 28gr of N133 before the bolt goes really stiff, this is giving about 3750 fps with the 39gr SBK. Accuracy is OK though, I have shot a couple of .25 MOA groups with no real load development.

Do you think I will be able to push this up on the second firing, at 28gr the brass was growing about 5 thou in length at the shoulder thus causing the stiff bolt