300 Norma Improved 35 degree

[h24]

Using that .336” bushing, you should run a seating ladder with the 245s somewhere between .080” to .120” jump.

I know that sounds odd for what we normally test with Berger bullets, but I’ve had really good luck in a couple cartridges (7mm and 338) jumping them a long ways out to .120”. And now I’ve been reading where some people are finding that the longer seating jump range is much more forgiving in ladder testing than the shorter .040” to .000” (touch) range.

When I was testing seating depth, I also ran into a sweet spot of .080"-.110" on my 6.5 Gap. This was done ladder style at 600yds.

 

[Alex Wheeler]

Thats not narrow at all if your testing at long range. Usually a node is about .5% of your powder charge. So in a 6BRA thats about .15 gn and in a 300 nmi thats about .45gn. And Id say to really top accuracy the nodes even a little tighter. You can definitely see a tenth in a BRA and three tenths in a nmi. Depends on what your calling a node though. Im looking for 3" or better at 1k from these. If your after sub moa for example, then you would say the node is much bigger.

 

[h24]

Thats not narrow at all if your testing at long range. Usually a node is about .5% of your powder charge. So in a 6BRA thats about .15 gn and in a 300 nmi thats about .45gn. And Id say to really top accuracy the nodes even a little tighter. You can definitely see a tenth in a BRA and three tenths in a nmi. Depends on what your calling a node though. Im looking for 3" or better at 1k from these. If your after sub moa for example, then you would say the node is much bigger.

I was just shooting ladders with the Labradar and looking for velocity nodes. Then was going to test with barrel tuner after that. I was under the impression that if my velocity was consistent that hopefully that would equate to minimal vertical at distance. Is that not the case?

 

[Alex Wheeler]

Nope, they dont necessarily correlate.

 

[Ledd Slinger]

I was just shooting ladders with the Labradar and looking for velocity nodes. Then was going to test with barrel tuner after that. I was under the impression that if my velocity was consistent that hopefully that would equate to minimal vertical at distance. Is that not the case?

No way. Consistent velocity doesn’t tell you much. It’s nice if velocity is consistent along with great accuracy but that’s not always the case. I’ve shot groups where they only had 1-2 fps ES and the accuracy was terrible. On the flip side have had groups run 20-30 fps ES and shoot 1/4 MOA

 

[h24]

No way. Consistent velocity doesn’t tell you much. It’s nice if velocity is consistent along with great accuracy but that’s not always the case. I’ve shot groups where they only had 1-2 fps ES and the accuracy was terrible. On the flip side have had groups run 20-30 fps ES and shoot 1/4 MOA

Even at long to elr distances? Man, I thought a 20-30 fps spread would surely show up at extended distances. Hmmm. Now I'm confused, haha. I was going to go the route of finding a load with a low Es, and then use barrel tuner to tighten groups. So testing powder charge at distance and recording grouping is recommended over how I was going to do it?

 

[Ledd Slinger]

Even at long to elr distances? Man, I thought a 20-30 fps spread would surely show up at extended distances. Hmmm. Now I'm confused, haha. I was going to go the route of finding a load with a low Es, and then use barrel tuner to tighten groups. So testing powder charge at distance and recording grouping is recommended over how I was going to do it?

I have been testing every load in my rifles at 870 yards this year so not ELR but far enough to tell that consistent speed does not always equal accuracy at long range. There are many 1K BR competition shooters that can attest to the same thing.

 

[tom]

Even at long to elr distances? Man, I thought a 20-30 fps spread would surely show up at extended distances. Hmmm. Now I'm confused, haha. I was going to go the route of finding a load with a low Es, and then use barrel tuner to tighten groups. So testing powder charge at distance and recording grouping is recommended over how I was going to do it?

The only tuning I've done at 2,000 (actually 2,075) was with my 338 lapua imp. However it was with v570, and has similar node width. About a grain at 871 yards, and about .3 at 2,075. The lower .7 that was there at 871 yards became 40-50 inches of straight vertical at 2,075. ES would be anywhere from 10 to 20ish at the very best 5 shot group....vertical ranging from 10 to 15 inches. The big vertical groups wouldn't have better or worse ES. Keep in mind numbers are being collected in small sample sizes, and using a consumer grade tool, lab radar in my case.


Tom

 

[h24]

I have been testing every load in my rifles at 870 yards this year so not ELR but far enough to tell that consistent speed does not always equal accuracy at long range. There are many 1K BR competition shooters that can attest to the same thing.

So are you guys doing power charge tests in a ladder and watching for minimal vertical dispersion/grouping along with Es? Or solely on vertical?

 

[h24]

The only tuning I've done at 2,000 (actually 2,075) was with my 338 lapua imp. However it was with v570, and has similar node width. About a grain at 871 yards, and about .3 at 2,075. The lower .7 that was there at 871 yards became 40-50 inches of straight vertical at 2,075. ES would be anywhere from 10 to 20ish at the very best 5 shot group....vertical ranging from 10 to 15 inches. The big vertical groups wouldn't have better or worse ES. Keep in mind numbers are being collected in small sample sizes, and using a consumer grade tool, lab radar in my case.


Tom

If I read that correct, At 2075, with an Es from 10-20fps you were seeing vertical of 10-15inches? 300gr Berger?

 

[tom]

If I read that correct, At 2075, with an Es from 10-20fps you were seeing vertical of 10-15inches? 300gr Berger?

Yes and yes, and of course once in a while a group will have a single digit ES, but sometimes 25 just as easy. If it's in tune on paper, then it will group. If it's out of tune, it won't group even if the ES is zero.

Tom

Edit to add. You can go back to page 16 here where I was doing early tuning on one of these 300 nimps, I wrote the velocity low to high next to the groups. It's basically just random when they correlate to a good/low vertical group. This was and is early on, and only at my 871 yard spot. And this gun wears a 34" barrel, so the velocities are a bit high compared to a "normal" gun with 245 bergers.

 

[Alex Wheeler]

I have had so much success with this design I have decided to release it to the public. I can not build them all and I get so many requests from people asking for info or having trouble with other designs. I just sent my resize reamer to Bullet Central, they will be selling the sizing dies. You can check with them in a few weeks. I am having JGS draw up another print so that gunsmiths wont have to hold headspace short to get proper crush, as that seems to be a point of confusion sometimes. I'll post the print here and will release it through JGS for anyone to order. I will throat it for the 230 hybrid and 245. You can shorten it up for the 215s but this case shines with the heavier bullets.

 

[rhovee]

Are you going to open the neck diameter some for the new lots of Lapua brass? They are a bit thicker. .3385-.339.

 

[nakneker]

I have had so much success with this design I have decided to release it to the public. I can not build them all and I get so many requests from people asking for info or having trouble with other designs. I just sent my resize reamer to Bullet Central, they will be selling the sizing dies. You can check with them in a few weeks. I am having JGS draw up another print so that gunsmiths wont have to hold headspace short to get proper crush, as that seems to be a point of confusion sometimes. I'll post the print here and will release it through JGS for anyone to order. I will throat it for the 230 hybrid and 245. You can shorten it up for the 215s but this case shines with the heavier bullets.

Well that’s a cool thing to do. I’m certainly enjoying the two 300 NMIs my cousin and I just got from you. Berger 230s, N570, T2 brakes, I still can‘t believe how Manageable the recoil is on these rifles.

 

[Alex Wheeler]

Are you going to open the neck diameter some for the new lots of Lapua brass? They are a bit thicker. .3385-.339.

No, mine is .343.

 

[Alex Wheeler]

Here it is. This is designed to have a crush fit on new Lapua cases. You can use a standard go gauge and chamber it short to get that crush or buy the gauge for this reamer. The freebore on the reamer is a compromise for the 230 and 245 Berger hybrids. Bullet Central will be making the dies for this again soon.

 

[Earnhardt]

What the COAL with the 245’s?
Thanks

 

[Tekardi]

Thank you for the print, wonder why you didn’t tight neck , I used 2425 with excellent result in Lapua brass

 

[rhovee]

Cause it’s made for hunting and many don’t want to turn necks. And hard to shoot the difference in a light weight hunting rifle.

 

[Ledd Slinger]

I don’t think tight necks make much of a difference in these large magnum rounds. Not as sensitive to neck tension variances. My last reamer was .339” neck to better test tension changes but all it really did was make me have to do more work turning necks. Better to run a no-turn neck with a bushing that gives .002-.004 tension and get after it.

Alex’s print is almost identical to my new reamer but I went with a wider throat diameter. I like it a little wider in case I ever get a production lot of “fat” bullets or a little dust in the chamber.