300 Norma Magnum Improved reamer and die release

[KH_Outdoors]

What neck tension are you running?

I believe it finishes at .0015" using a .307" neck turn mandrel

 

[Schw15]

I believe it finishes at .0015" using a .307" neck turn mandrel

Nice I'm going to try a .307 as well to see if my numbers shrink on es.

 

[Alex Wheeler]

N568 is the best powder I have tested in my 35* 300 NMI. Truthfully it was so good I stopped testing other powders (other than H1000). 10 shot strings are normally single digits to mid-teens ES's. N568 is EXTREMELY temp stable. 40-80*s zero gain in velocity. I compete in ELR, so I watch this stuff very closely. I could not believe how temp stable it is.

89.5 grains of N568 is just over 2900 FPS in my 26 in Bartlein with 245's / .275 FB. I am currently jamming them .012, but will redo seating depths with the rifle falls out of tune. This barrel has 585 rounds on it. Early in its life it preferred .010 jump and held that tune for over 350 rounds.

Primers make a difference in ES. Test 210's and 210 match- they may end up better than 215's or 250's.

.012 in worked great with the 245 as well for use for the 2k yd guns. Be careful with the 210s. Have a guy running a 338 version of this with N570 and the 210s shot the best. But occasionally he gets a slight hang fire. Especially in the cold I would stick to at least a 250 cci. Which is still a mild primer.

 

[Schw15]

.012 in worked great with the 245 as well for use for the 2k yd guns. Be careful with the 210s. Have a guy running a 338 version of this with N570 and the 210s shot the best. But occasionally he gets a slight hang fire. Especially in the cold I would stick to at least a 250 cci. Which is still a mild primer.

The 338 version of this seems awesome. 2900 with 300 berger n565? 28 inch barrel?

 

[Marine sniper]

.012 in worked great with the 245 as well for use for the 2k yd guns. Be careful with the 210s. Have a guy running a 338 version of this with N570 and the 210s shot the best. But occasionally he gets a slight hang fire. Especially in the cold I would stick to at least a 250 cci. Which is still a mild primer.

Just to add a little to that. I am under the impression (just an opinion at this point) that some powder is harder to light than others.
Too bad you don't do the 2K benchrest stuff anymore- I would make the drive for it. I took your advice and built a 338 LAI for my ELR light rifle this year (Earl F. put it together.). I have a 300 NMI as well obviously, did away with the 33 XC.

Will be fun pitting the 300 NMI and the 338 LAI against each other at distance.

 

[KH_Outdoors]

Nice I'm going to try a .307 as well to see if my numbers shrink on es.

On my last barrel I tested the neck tension using a .307" & a .3055" mandrel. The .307" resulted in a little better grouping and lower ES/SD so I've just stuck with it.

I also tested the 215m vs CCI250 primers on that barrel and it seemed like 215m's were always a little better. Might be worth a test to go load up 10 of each and go do a test. See if there are any standouts!

To be honest though, I'm more of the opinion that you pick one (neck tension & primer) that has historically worked well for others and stick with it for your load development. I'm sure that it can and has made big differences for some, but most likely very very minor for most. Especially when you're starting with known good combinations.

Might also find that once you increase the sample size enough it's all the same too. One way to find out!

 

[Alex Wheeler]

Just to add a little to that. I am under the impression (just an opinion at this point) that some powder is harder to light than others.
Too bad you don't do the 2K benchrest stuff anymore- I would make the drive for it. I took your advice and built a 338 LAI for my ELR light rifle this year (Earl F. put it together.). I have a 300 NMI as well obviously, did away with the 33 XC.

Will be fun pitting the 300 NMI and the 338 LAI against each other at distance.

Im still pretty interested in the 2k. My money would be me back in Mt, and that will be a main priority. Theres a ton of work to be done in the 2k stuff.

 

[Alex Wheeler]

The 338 version of this seems awesome. 2900 with 300 berger n565? 28 inch barrel?

N570 and at least that fps.

 

[KH_Outdoors]

N570 and at least that fps.

@Alex Wheeler what are your preferred powders in the 300 NMI with 230/245's?

 

[Schw15]

N570 and at least that fps.

Would n565 not be a good powder for the 338?

 

[EFouraker]

.0036- to .0046 of throat death per 100. The bigger number as the barrel got more worn.

I think the primer concerns over ignition in cold weather are overblown for the most part. I was out shooting the over day in 30* weather and did not have an issue. My primary hunting rifle is a 338 LAI that I run 98.6 grains of H1000 in with 210's and have never had a problem with ignition in Washington state and Idaho

I've had hang fires with n570 in magnum cartridges when the temps get cold.

Alot of times guys shoot in cold temps but the ammo doesn't "cold soak". It goes from the house, to the warm truck, and then gets shot fairly quickly when at the range.

I would never run them in a 300nmi for a mountain hunting rifle that will see 0deg lows and doesn't get above freezing for several days.

It's probably ok for elr comps where it's 100deg in July.