300 Norma Improved load help

[nodakhunter]

Running a 35º improved version using RL33 behind a Berger 245. The speed is there for sure but the accuracy is hit and miss. Not seeing great vertical dispersion at range and the groups are mediocre. Has anyone ever tried H50BMG in one of these improved Normas? Any advice on a starting load with the 245? I know the go to powder is N570 but finding any is like trying to hunt down a unicorn. I have a bit of H50 on hand which got me wondering if I could improve my results with it.

Calling the 300 NMI experts: @rpierce @Alex Wheeler

EDIT: 27" barrel, 1:8 twist, .255" freebore

 

[rpierce]

Running a 35º improved version using RL33 behind a Berger 245. The speed is there for sure but the accuracy is hit and miss. Not seeing great vertical dispersion at range and the groups are mediocre. Has anyone ever tried H50BMG in one of these improved Normas? Any advice on a starting load with the 245? I know the go to powder is N570 but finding any is like trying to hunt down a unicorn. I have a bit of H50 on hand which got me wondering if I could improve my results with it.

Calling the 300 NMI experts: @rpierce @Alex Wheeler

EDIT: 27" barrel, 1:8 twist, .255" freebore

Its been a while since I messed with h50bmg but it worked great. Youll need to use a drop tube. Make sure your using .004 neck tension. Ive found that more tension has decreased ES and made the accuracy windows wider. Atleast in the combos Ive tested. However I anneal everytime with an AMP annealer. Seating pressure is the same every time. Have brass with over 30 firings on it.

 

[nodakhunter]

Its been a while since I messed with h50bmg but it worked great. Youll need to use a drop tube. Make sure your using .004 neck tension. Ive found that more tension has decreased ES and made the accuracy windows wider. Atleast in the combos Ive tested. However I anneal everytime with an AMP annealer. Seating pressure is the same every time. Have brass with over 30 firings on it.

Ryan - thanks for the response. I'm running .003 neck tension right now if memory serves me correct. Might mess around with RL33 a bit more but am glad to hear that you've had good luck with the H50BMG.

 

[Alex Wheeler]

First, .255 is too short for a 245. You very well may be into the donut if there is one, you wont make it shoot no matter what if thats the case. But I need a lot more info. Info on the rifle and how you have tuned it so far. Who built it, and have they given you any thoughts?

 

[Willys]

Try 230's

 

[rpierce]

Try the 220s if you can find them also. They can go almost as fast as the 215s and the bc is the same as the 230's. Theyre pretty much identical to the 245 for performance but flatter. Theyll work great in that freebore as well. Customers and I have tried em in the norma and prc and were very surprised at the velocity we got before pressure was seen. In a 24" 300 PRC and h1000 we didn't get ejector marks til 3080 fps. Theyve shot phenomenal. I have a benchmark carbon 10tw 26" Ill be spinning up this week for myself and running that bullet exclusively in it with N568.

 

[nodakhunter]

First, .255 is too short for a 245. You very well may be into the donut if there is one, you wont make it shoot no matter what if thats the case. But I need a lot more info. Info on the rifle and how you have tuned it so far. Who built it, and have they given you any thoughts?

I built this rifle primarily to be a hunting rifle and am using a CIP detachable mag. So I'm limited to 3.75" OAL if I want to mag feed, which would be preferable. Pic included is where that bullet is seated at max mag length.

The gun also had a +P throat cut. When I got the rifle back, I loaded rounds at max mag length with RL33 at a few different charge weights. It shot a couple of groups around .5 MOA at 95.6 grains, but it was erratic. One group would be .5 MOA, the next 1.5. This charge gave me a velocity of just over 3000 fps with no noticeable bolt lift or other signs of pressure, but I wanted to see if it could do better.

Shot various charge weights from 93-95 grains earlier this week, and the 93.0 grain load produced several sub-0.5 MOA groups @100 yards. Took it to 1000 and saw very little vertical spread which I had struggled with at the higher charge weights. Planning on doing further testing at around 93 grains.

Rifle info: BAT HR, Helix 6 27" 1:8 twist barrel, Game Warden stock, Bix n Andy trigger

Edit: Do NOT use my load data in your rifle! This gun does not have a standard throat!

 

[nodakhunter]

Try the 220s if you can find them also. They can go almost as fast as the 215s and the bc is the same as the 230's. Theyre pretty much identical to the 245 for performance but flatter. Theyll work great in that freebore as well. Customers and I have tried em in the norma and prc and were very surprised at the velocity we got before pressure was seen. In a 24" 300 PRC and h1000 we didn't get ejector marks til 3080 fps. Theyve shot phenomenal. I have a benchmark carbon 10tw 26" Ill be spinning up this week for myself and running that bullet exclusively in it with N568.

I'll look around for some. Any issues using them on game with the reduced tips?

 

[rpierce]

I'll look around for some. Any issues using them on game with the reduced tips?

From what I've heard they work great on game.

 

[Willys]

Carbon Barrel…… can be finicky with consistency with RL 33 in my limited experience. Keep playing with it. Extended throat doesn't help with RL33 - likes pressure. N570 if you can find some. Let us know…..

 

[nodakhunter]

Carbon Barrel…… can be finicky with consistency with RL 33 in my limited experience. Keep playing with it. Extended throat doesn't help with RL33 - likes pressure. N570 if you can find some. Let us know…..

Yep will do. Hoping that those small groups at 100 hold out to distance. I'll hopefully have a report by this weekend.

 

[Alex Wheeler]

I suspect your throats longer if thats your touch point. So your ok if you dont seat them too much deeper. .5 followed up with 1.5 sounds like less of a load issue and more of a mechanical issue. Thats a lot of difference. If your lower load is solid then your good but if you see that kind of variation again, start checking out the rifle first. I also understand its hard to find powders. But if you dont find something relatively soon, even swapping a bullet or two then your will burn out your barrel trying to force feed it. If Rl33 just does not seem to be working for you then your better off stopping until you can find others to try. If a barrel doesnt like a powder theres nothing you can do to fix that.

 

[nodakhunter]

I suspect your throats longer if thats your touch point. So your ok if you dont seat them too much deeper. .5 followed up with 1.5 sounds like less of a load issue and more of a mechanical issue. Thats a lot of difference. If your lower load is solid then your good but if you see that kind of variation again, start checking out the rifle first. I also understand its hard to find powders. But if you dont find something relatively soon, even swapping a bullet or two then your will burn out your barrel trying to force feed it. If Rl33 just does not seem to be working for you then your better off stopping until you can find others to try. If a barrel doesnt like a powder theres nothing you can do to fix that.

Yep that's what had me confused as well. I checked all screws and bolts on the rifle and everything seems to be in order.

On the bright side it seems to be liking the lower load. It's hard to shoot tight groups at distance in the constantly switching ND winds but the vertical dispersion on this load out to distance seems to be a lot tighter. If N570 shows up sometime soon I might try that for a bit, but this load is shooting good enough for now.

 

[Quicksilver338]

Using all that rl33, are you keeping up on cleaning the carbon out of it? Not just the loose stuff, the deep caked on deposits that like to show themselves with these rifles and powders like that.