John MH

.300NM alongside 33XC and 37XC, base dimensions very similar.

1 minute ago, meles meles said:

We generally tend just to neck size our brass and keep a separate batch of cases for each rifle. Ought we to be doing differently if we go down the .300 route? 

No not necessarily, every rifle chamber is going to have slight variations. Neck sizing only might work for you but when shooting against the clock FL sizing reduces the chances of having to faff around to get a cartridge to chamber.

2 minutes ago, Ronin said:

Just full length size the brass 

I did with a Whidden Bushing FL Sizer die, might be my chamber of course, but the Tubb 33XC die reduces the base from 0.5850" (fired in my chamber) to 0.5820", virgin unfired Lapua Brass measures 0.5815" at the same place on the case head. The Whidden FL Bushing die reduced the base to 0.5845", CIP specs a chamber measurement of 0.5854" at the same place on the case, however without a fixture to hold the case to ensure measurement in exactly the same place on each case there will be some variation in dimensions although it (the 33XC die) definitely reduces the base dimension.

On 5/23/2019 at 10:03 PM, meles meles said:

Come on, bald monkeys. Back on topic. .338" or .300" Norma Magnum ?

33XC Dies not entirely off topic. A problem I experienced on my last outing with the 300NM and of the second firing of the brass was that the base of the case just forward of the case head base was not getting sized down back to original 'virgin' brass size, this caused several cases (approx 15%) to be hard or impossible to chamber. Apparently a problem experienced by others shooting 300NM from forum research, a solution offered byDavid Tubb was that his 33XC spec custom resizing die will 'small base' the 300NM just that little bit more than standard dies; well it sure does and the extra squeeze looks to have solved the problem. 😀

.338 alongside .30 Cal, Tubb nose ring clearly visible. The bullet also have a clearly visible raised 'sealing rings/drive bands' similar I suppose to those found on artillery projectiles.

They have Tubb’s nose ring.

198s

52 minutes ago, terryh said:

John - Flatlines?

T

😀

New bullets to try in the 300NM, never had a vacuum packed bullet delivery before:

There is not much need to be able to shoot ‘Mag Length’ as far as I can see, so whilst magazine feeding might be attractive it’s not really necessary.

Not 300 Norma or .338 Lapua Magnums but should be fun getting it to shoot. I’m going to give the 33XC a tryout and maybe move up to 37XC next year.

Managed to get 3100 FPS with 225 Grain ELD Match elevation predictions out to 1450 yards were spot on. It really makes those 12” round steel gongs spin when hit 😀

Hoping to get some 198 Grain Flatline bullets to try later on.

Anyone using 33XC or 37XC?

New unprimed Winchester brand 22-250 cases, £28.00 £20.00 per hundred.

5 minutes ago, Artiglio said:

pretty easy to check , rco asks for say 3 rounds, two are fired over a chrony , 3rd pulled and bullet weighed. 

Not a practical option on a rifle range, lot's of issues with authority to possess that type/calibre or ammunition, scales and chronograph calibration and accuracy, delays and arguments. Self certification is also impractical, what form does it take, what happens if there is an error in accredited published loading manuals and who accredits the loading manual. So many holes in this looks like it was thought up by someone of limited knowledge or practical experience of hand-loading.

It was very impressive.

Well after a problematic first day's testing at 110 yards, which I have not got to the bottom of yet, I reloaded my first batch of fire-formed Lapua cases. On initial firing the shoulders on the cases moved forward 0.010", bumped back 0.0025", neck tension set to 0.003", filled with 89 grains of RS80, Fed 215 LR Magnum primers and a Hornady 225 grain ELD Match.

I managed to get a muzzle velocity of 3100 fps with absolutely no pressure signs. Put that into AB App for sight elevation corrections for 650 yards, 900 yards, 1133 yards, 1240 yards, 1300 and 1400 yards.

Elevation corrections were pretty much spot on needing a maximum change from 110 yards to 1400 yards of 35.25 MOA. Wind was gusting right to left between 15 to 25 MPH so at 1400 yards I was holding off 11 MOA. Mostly managed 1st round hits at each distance with a 2nd round hit on the 1400 yard full sized IPSC. Pretty pleased with the results so far.

Thanks to Terryh for spotting for me.

Just bite the bullet and stick an order in.

Latest Mod State:

The Autothrow works really well and the replacement breeze break lid has made a big difference to the stability of the set up. I do prefer the taller breeze break but can live with this as it is for now.

Had not put a lot of thought into it but am looking at using less than 200 grain bullets and N560 (around 70 grains).

Have ordered a 33XC reamer and 100 pieces of Peterson brass as the ATR now holds the KO2M record.

Mine's in the UK waiting to clear customs. Going to use the first 50 rounds to fire form the cases and the start on serious load development. First outing will be on Bodmin Moor around 29 dec 18.

Well rifle ships out of the USA on Sunday and is expected at the East Midlands cargo agent on Monday, so I will hopefully have it before Christmas. Limited on powder choice and availability so going to start with RS70 and N560, intend to move onto RS80 in the New Year. There is some load data available for N560 so I'll use that for fireforming my Lapua cases.

Rifle is a Tubb Adaptive Target Rifle, a switch barrel design and its coming with both 300NM and 6XC barrels. Will be interesting to see how it performs, if its anything like my T2k it will be a tac driver. Got a very nice S&B 5-45x56 PMII to sit on top in a Spuhr uni mount with a Aimpoint Micro H2 sat on the side.

Will need to swap notes.

My thinking is to go with the Hornady 225 Grain ELD-M to start with, still waiting for rifle to touch down but everything ready to go. Don't think I'm going to need an adjustable base and as its a multi cal rifle with a 20 MOA integral rail I'm thinking maybe a 20 or 30 MOA base for the 5-45x56 PMII.