Question: neck bump 300 wsm

Varmint Hunter

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Starting with a new case, shoulders move forward with each firing. You may be able to just neck size a few times, but that depends on how much pressure the load generated and how hard or soft the brass is. Sooner or later, brass will get tight and you will need to move the shoulder back or resize the entire case.

It's probably easier and more consistent to FL size from the beginning and to adjust the die down just enough to ensure a smooth entry into the chamber. Sizing too much will cause headspace issues and shorten the life of your cases considerably. A little trial and error as you set up your die is all it takes to find just the right fit. Having a headspace gauge is helpful but not needed.
 

L.Sherm

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Don't assume new cases will not need the cases bumped for a couple firings.
My brand new ADG 300wsm case were exactly what my fired case were at the datum line. MEASURE MEASURE!!
Throw the die instructions in the garbage and set them up according to how much you wanna bump the shoulders using a comparator.
 

spladi

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I need to bump the necks on my brass. I just got a bump gauge and i have a set of regular rcbs full length dies and a rcbs nech bushing die. Will either die work to bumb the neck ?
My RCBS FL Die will...........my older Redding Bushing NK Die will not.......... There is such a thing out now that FL sizes and uses a bushing.
 

TexSavage

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I set my Redding full lenght dies years ago per manufacturers instructions. All worked fine, rifle shot just under MOA out to 450 yards. Then some years ago I watch a video by Broz over at Long Range Only about how to set up a FL die for just bumping back the shoulder. It made so much sense that I reset my die and now bump backabout .002

End results are sub .5 MOA at 450, better SD, much longer case life. Brass is difficult to get at a price where it might not matter, but I'm using Norma brass and it's pricey plus, I believe in getting the most out of my equipment and brass. Most of my Norma cases have 4 to 6 reloads on them. My retired Federal Nickel plated have at least 11 reloads on them as do my WW brass. The one brass that had poor life has been the Nosler brass. I had three case head seperations on resizing after 3 reloads. I was concerned and checked my Federal Nickel, Winchester brass, and Norma brass and none showed signs of case wall thinning near the case head. The Norma did on multiple cases, so I turned it into dummy practice rounds I use for dry fire practice.

My two cents worth, YMMV!

EDIT - I do shoot a 300WSM
 
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DWier

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I use lapua brass in my 6.5 needmoor. Bump shoulders back .004 with FL bushing die. I get 0.25 MOA. You also need to check case length with a case length gauge as overall length increases with each firing but with hard brass like lapua and Peterson it's a slow progression.
 

cr30378

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i had 4 rounds on the Winchester brass before i bumped them, length was still as i originally trimmed them+.005 or so. shoots a .276 at 100
 

pony doctor

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I can’t get onboard with neck sizing because at some point your going to have to full length resize. So I find it rather pointless, I think it’s one of those old things that just kept going from “that’s how daddy did it” type logic. At least that’s why I did it years ago. It probably did gain accuracy and brass life at the time when nobody annealed and set up dies to way oversize.

A bushing full length die and Redding comp shell holders and a guy can easily do the same thing all the time every time which imo leads to more consistency. There are plenty of other ways, but that’s the easiest I have found especially if your loading for multiple chambers with the same dies.
Anneal the cases from the neck to 1/4 inch below the shoulder, full length resize them, trim to recommended length ( I recommend Henderson Precision Case trimmer) In my opinion this should result in consistent neck tension which should result in minimal velocity spread.
 

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