Berger to introduce 7mm 195 gr EOL Hybrid Hunting Bullet

[Edd]

That is what I was wondering.

What is the standard neck size? For some reason .315 seems familiar

I don't know anything about a "standard" neck size. If you look at SAAMI specs on 7mm chambers, you will find neck diameters from .315" to .323".

I can't remember ever measuring new brass that had a neck thickness less than about .0135". I suspect your necked down brass will be in the .014"-.015" range, maybe thicker. You can do the math using .0145".

Brass neck thickness .0145" x 2 = .029"
Bullet diameter........................= .284"
Neck/chamber clearance.......... = .004"

Minimum neck diameter........... = .317"

 

[chuckhammer]

I don't turn the necks on my improved 7-300 WM that I call the 7mm Valkyrie. I can also use trimmed .300 H&H for a longer neck and they come out to .312-.313 neck diameter when loaded. This is WW Super headstamp.

My reamer print shows a .316 neck diameter. If I do another one I'll reduce it to .314 min.

 

[mrb1982]

Very interesting. I have some hornady brass I am going to use. From what I have read, dimensions are pretty similar to Winchester brass as far as weight and thicknesses. Sounds to me that I am just going to have to order my own reamer. I haven't found what I am looking for on the rental sites so far. Kinda hate to buy a reamer to use one or maybe two times at the most but I might be forced to.

 

[Edd]

If you already have the brass, measure it. Then you will know what neck diameter you need.

 

[BigSwede]

Mine is .317 but I would do .316 or .315 if you plan on using win/horn/rem brass. I think I may be better served by RWS but so far so good. My final sizing is with .313 bushing with virgin brass it's great but once fired needs a .311 or .312

 

[mrb1982]

I could see that. I did see one reamer with .315. Might be a happy medium. I need to get my brass sized up the way I want and the measure.

 

[kennyg]

i have a 7 SAUM using Remington brass and the necks on loaded rounds measure .315.
I would personally want at least .004 clearance-I am just not sure there is enough benefit to going tighter but I could be wrong.

 

[esshup]

7mm Allen Magnum uses .338 Lapua Brass as a parent cartridge. loaded rounds measure .315" - .3155 without any neck turning.

 

[Broz]

From what we are seeing from the 7-300 with a MV of 2950 fps. I am not sure I want to run the 195's a lot faster and use them on game under 500. Expansion is very big at the 2500 fps impact velocity. Expect big exits on antelope and huger destruction to the vitals with no exit on elk at these distances.

Jeff

 

[mrb1982]

Sounds devastating! I like it! Lol I might just have to call PTG and see what they have. I find it hard to believe they haven't made a reamer at some point that is .315-7 with some sort of relevance to the FB I am looking for.

 

[calinb]

I don't know anything about a "standard" neck size. If you look at SAAMI specs on 7mm chambers, you will find neck diameters from .315" to .323".

I can't remember ever measuring new brass that had a neck thickness less than about .0135". I suspect your necked down brass will be in the .014"-.015" range, maybe thicker. You can do the math using .0145".
<snip>
"

Agreed. WRT my little 7mm-300 RCM chambering, I had Dave grind my reamer to require a light turn of the necks. I could have had him make the neck larger and not have to turn brass, but I wanted to be able to true-up the necks. I'll be custom cutting a Wison bushing style neck die from a blank too.

 

[AZShooter]

KennyG and others,

I found this on Accurate Shooter forum under 7mms:

"Chambering can play a role as well. Jerry Tierney, a past NBRSA 1000-yard champion and .284 Win "guru", has observed that overly tight chamber neck tolerances can cause accuracy problems. Jerry says "some guys who were running minimal neck clearance .284 chambers weren't getting the accuracy they expected. If you open up the neck to allow more clearance, say .0015-.002″ per side, that seems to solve the problems. I can't tell you exactly why–maybe it allows a 'cleaner' bullet release–but easing the neck clearance has helped many .284 shooters get better results."

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I thought about this clearance when I built my 7-375 Ruger. The brass is quite thick after necking down. I asked Dave Kiff to make me a .317" chamber neck and turned the necks to .313" for a total of .007" clearance.

My 284 winchester reamer has a .315" neck and the necks are turned to .013" for a .005" total clearance.

S bushings are used with both chamberings and they work fine with excellent accuracy. Both are hunting rifles.

I have a 30 BR that is using a .001" per side clearance. Actually had it down to .0005" per side at one point but it was too much maintenance to keep it going. Accuracy didn't suffer with either clearance. Sure wouldn't consider that for a hunting rifle!

LRH is a great site where we can learn from each other. Keep this tread going.

 

[JARHEAD1371]

KennyG and others,

I found this on Accurate Shooter forum under 7mms:

Thanks for passing that along! I'm in the planning stages for a wildcat to push the 195 to an easy 3100+ fps and I wasn't sure how much neck clearance was needed.

 

[IdahoCTD]

I specified .319" for my Norma Imp. Norma brass necked down came in at .315-.316 with a seated bullet. I'll use 423 Dakota brass and will have to neck turn it anyway as it's about .020-.022" neck wall thickness when it is necked down that far. I was only about .0025" total clearance in Norma brass with my .30-338 Norma Imp and wanted a little more on the 7. I've heard before that 7's can be finicky with too little clearance so I went .001" more and can always turn necks if need be.