Thread: 284 win getting low velocities

Hello you lot,


What sort of velocities are you guys with short barrels (17 inch)? rifle is a Tikka t3 7mm08 re-chambered.

I'm only getting 2640 fps over the chrono and load is 51.5gr of Reloader 17, fed 210 primer, norma brass and 162 ELD-m. This load is definitely hot in this barrel with extractor marks at 52.5gr during development.

I've been hoping to get around 2800 fps no cigar yet.

Any tips? the rifle isn't as long throated as long as some i've seen on here but would that make much difference?

magnum primers worth a try?


Cheers

The .284 is an overbore cartridge and is designed for longer barrels with moderately slow powder (factory ballistics are based on 24" barrels). You could carefully work up some loads with a slightly faster powder but you are never going to reach factory velocities with a 17" barrel. 2600 fps is a perfectly respectable velocity for anything out to 250-300 metres.

Who rechambered it, what is the neck diameter of your chamber, and what brass are you using abd what's the diameter of the neck on a loaded round.

I've been thru all of this with my 17" 284 and finally sorted it. I run a 162g Amax at 2700 now, which goes very well.

I opted to use the tight neck reamer .317. And after necking up 6.5-284 lapua brass, the base of the neck measures .319. It needed neck turning right down into the shoulder to remove that thicker section from where some of the shoulder material was formed into the base of neck.

the short barrelled 284 win has become somewhat of a trend here as its pretty efficient and can work well in a short barrel.

the rifle is built to shoot up to 600m or so which should be quite doable.

thanks for the tip though mate!

your original posts on your 284 was one reason that I wanted to do the conversion! rifle is set up similar to yours.

Greg at custom guns in Invercargill did the chamber and the throat isn't a tight neck. I wanted a little more room to play with with different brands of brass/ I don't have a neck turning set up.

Brass is factory Norma .284. can check diameter of a loaded round tomorrow

Measure the neck diameter of the fire cases, then measure the neck diameter of neck with bullet seated and pm me. Happy for you to call me for a chat about it all.

That does seem a little slow. That said, it is only a 17 inch Barrel and 2650 with the eld m is still plenty to reach out to 500.

Norma brass is softish and I notice does tend to stamp a little easier than lapua.
If it shoots as is I wouldn't worry. Animals not going to no5ice that extra 50 fps

Have you verified your fps by shooting at range?
My Chrony reads 70-75 fps slow under all conditions.

I’d agree a 162 travelling that ‘slow’ is still fast...

hi kiwi303.

I have a 284win 20 inch tikka 7mm08 barrel, gun works did the work. only managed about 2670 with 51.5 gr rl17 hitting pressure signs.
that was lapua brass necked up. seems low like yours compared to what others have been getting, a suppressor for me might increase it a bit. i assume yours is suppressed? I'm planning on trying 2213sc so will let you know how that goes, can't imagine it going much faster.

How will adding a suppressor increase velocity?

I've heard of it increasing velocity, weather its true or not I'm unsure. some guy at a gong shoot was claiming 90 fps increase on his rem mag. i will find out when i get one for my 284.

Originally Posted by c-dog

hi kiwi303.

I have a 284win 20 inch tikka 7mm08 barrel, gun works did the work. only managed about 2670 with 51.5 gr rl17 hitting pressure signs.
that was lapua brass necked up. seems low like yours compared to what others have been getting, a suppressor for me might increase it a bit. i assume yours is suppressed? I'm planning on trying 2213sc so will let you know how that goes, can't imagine it going much faster.

Read my posts above about neck diameter in your chamber.

Hey GWH, did your right neck affect pressure/velocity? Did you have trouble chambering them before neck turning?

Tight neck