6.5 284 chamber

[jmsarron]

I have just finished building a 6.5 284, rem 700 action, 27” Shilen select match barrel 1-8” twist, HS tactical stock, jewel trigger.

I have just finished prepping 200 lapua cases, I wasn’t very happy with that batch, the flash holes weren’t 100% centered, but I uniformed the flash hole sizes and primer pocket depth and turned the necks. I had to turn the necks .003” to make them uniform, now my loaded case neck diameter is .292”.

My question for anyone who can give me advice is this:…………… My chamber neck diameter is .300”. Is that .008” expansion in by brass a problem? Would it affect accuracy? Will it work harden my brass rapidly, or is .008” acceptable?

 

[olsingleshot]

Lapua told me that their loaded 6.5x284 brass has a .296" neck diameter. Hornady has a .299. You should have .002 room to expand. Once fired brass will probably give you better accuaracy in the situation you are in.

 

[jmsarron]

6.5 284 is standardized and when you order a reamer for it they send you one with a .299" neck dia,which 90%of the time will blow out and extra .001"). I didn't think that was going to be a problem considering lapua brass had i loaded diameter of .296", or so i thought... The loaded brass was .294" + or - .002"! buy the time i made them all uniform the diameter was .292".

I'm thinking of getting different brass with thicker neck walls and staring over, befor wearing out the barrel with unnecessary load development. What a shame, we all know how long it takes to PREP NEW BRASS.

 

[Rust]

When checking neck thickness variations of my first batch of Lapua 6.5 X 284, I was initially somewhat disappointed. Previous experiance with other brass led me to sacrifice a couple of pieces to see what was going on. Turns out that when the inside chamfer was a bit more aggressive, the neck thickness variations pretty much disappeared.

The other thing I've started doing was ordering the brass first for a new rifle, and ordering a chambering reamer based on the mesurements. Brass lasts a LOT longer and needs annealing less often that way. And by the way, given my druthers, I'd never turn a piece of brass if I could help it.

Another hint if you have to trun brass. Take the cutter from your turner and have a tool and die shop put the same shoulder angle as the brass you are turning. Keeps the thickness of the shoulder more uniform.

 

[mikecr]

Too late to help, but this is a great example of a mistake people building a guns commonly make.

#1 Get reloading components in-hand prior to making any decisions about a rifle design.

You should have bought brass and bullets before anything else.
You should have made a dummy round, sat it on the bench with calipers, thickness mic, and a blank reamer print.
Later, with your ordered reamer set, die blanks, barrel blanks and action in-hand, you'll have a starting point for your builder to make exactly what you expect.

Else your left to this 'standardization' you seem snowed with..
Think about it.