6.5-284 Set Up for Peterson

[G Love]

So since Lapua isn’t making brass 6.5-284 anymore, has anyone had a reamer cut for Peterson brass, and using Peterson brass? Thinking about having mine rechambered. Lapua in the later batches must have changed something in the case body. I can’t get a fired case to chamber without serious bolt pressure. The fired neck is .296 and my gunsmiths reamer is set up for a .298 and it’s not a bump problem either. Trying to decide what to do.

 

[Walt Krafft]

Overall case length ok?

 

[G Love]

Overall case length ok?

It is. I think we’re just dealing with a tight body on the reamer or something.

 

[JLittle]

What’s the base or .200 line on new and fired Peterson? Lapua is .498 ish. Fired .499/500 (in my chamber). I have a 6.5/284 DDS reamer that cuts the base much smaller for use with Winchester brass. From when that was all that was available. Lapua will not chamber in it. It helped keep the primer pockets from expanding. Best get a reamer print from the smith. 6.5/284 can be all over the place since it was a wildcat previously. You are correct in that it is likely in the body.

 

[DHuffman]

Don't overlook the diameter at the body shoulder junction.
I bought a reamer here in the classifieds. No turn Lapua blah blah blah that won't chamber a new piece of Lapua brass.
After a lot of measuring and using different dies with different measurements it was obvious the reamer was not big enough for virgin brass at the body shoulder.

 

[G Love]

What’s the base or .200 line on new and fired Peterson? Lapua is .498 ish. Fired .499/500 (in my chamber). I have a 6.5/284 DDS reamer that cuts the base much smaller for use with Winchester brass. From when that was all that was available. Lapua will not chamber in it. It helped keep the primer pockets from expanding. Best get a reamer print from the smith. 6.5/284 can be all over the place since it was a wildcat previously. You are correct in that it is likely in the body.

Not sure. I’ve never held a piece of Peterson 6.5-284. But apparently Lapua IS still making it. They just paused for a while. I’m taking it to the smith this week. Have some other stuff I need to pick up / drop off anyhow.

 

[ELR LVR]

So since Lapua isn’t making brass 6.5-284 anymore, has anyone had a reamer cut for Peterson brass, and using Peterson brass? Thinking about having mine rechambered. Lapua in the later batches must have changed something in the case body. I can’t get a fired case to chamber without serious bolt pressure. The fired neck is .296 and my gunsmiths reamer is set up for a .298 and it’s not a bump problem either. Trying to decide what to do.

.296 neck vs .298 chamber are still pretty tight of a fit,
Theoretically it should be fine, but in reality, you may wanna turn your necks down another .002"
I have one rifle that theoretically has enough neck clearance
but after I fire a case, the neck dia is the same before and after firing.
I have fitted things together before that when measuring with mics, have .001" clearance
but still wont fit together, its baffling I know
So consider that some bullets may have different pressure ring measurements etc.
Temp differences between the 2 metals can affect fit etc.
Also consider if the bullet is not inserted perfectly concentric, it will oblong the outside neck dia of the case. making it larger than your normal .296" - another reason for a seemingly tight fit.
----------------
in any case, maybe try small base sizing it if you feel your neck clearance is still fine.
my 6.5x284 Lapua brass shows to have the same outer dimensions as my 284 Winchester brass once sized
I can use either/or brass for my rifle, you should be able to also if sizing is doing its job
----------------
if not, then maybe look in the bore with a borescope and see if the neck is gouged from the throater or reamer which places protrusions into the inner dia. interfering with things
it may need to be cleaned up, sanded smooth, lapped etc.
Scotch brite on a mandrel spun in a drill can work for this
----------------
One other thing to consider, is the clearance at the head of the case vs the chamber
there should be minimum of .002" clearance, preferrably .003-.004"
not all sizing dies squeeze down this area behind the .200" line is why
A correct dia straight wall pistol sizing die can accomplish sizing this area if FL rifle dies wont
Maybe a .50 cal variant or something will work for this
I have used pistol dies to squeeze down the head slightly for some cases
My 284 brass measures between .495-.498 at the head (not rim)
but can expand to .500" if loaded hot so needs to be squeezed down somehow
When I had my first custom reamer made by Manson I spec'ed out .500" at the head ....
..."Thinking" that things may not always cut perfectly, that when I cut the chamber I would allow for a non perfect setup, side pressure on the reamer etc, to slightly cut an oversize chamber...to maybe .501"
so I spec'd out the reamer to be slightly tight but still with brass clearance thinking I would compensate for possibly cutting oversize
but Nope, it cuts the chamber true to size at .500" which bit me and is too tight
So after cutting a chamber I have to also enlarge the chamber in the head area another .001" to .002" or else I get clickers and stuck cases.
So you also could check the dimension of your chamber in the head area to be sure it has enough clearance.

 

[G Love]

.296 neck vs .298 chamber are still pretty tight of a fit,
Theoretically it should be fine, but in reality, you may wanna turn your necks down another .002"
I have one rifle that theoretically has enough neck clearance
but after I fire a case, the neck dia is the same before and after firing.
I have fitted things together before that when measuring with mics, have .001" clearance
but still wont fit together, its baffling I know
So consider that some bullets may have different pressure ring measurements etc.
Temp differences between the 2 metals can affect fit etc.
Also consider if the bullet is not inserted perfectly concentric, it will oblong the outside neck dia of the case. making it larger than your normal .296" - another reason for a seemingly tight fit.
----------------
in any case, maybe try small base sizing it if you feel your neck clearance is still fine.
my 6.5x284 Lapua brass shows to have the same outer dimensions as my 284 Winchester brass once sized
I can use either/or brass for my rifle, you should be able to also if sizing is doing its job
----------------
if not, then maybe look in the bore with a borescope and see if the neck is gouged from the throater or reamer which places protrusions into the inner dia. interfering with things
it may need to be cleaned up, sanded smooth, lapped etc.
Scotch brite on a mandrel spun in a drill can work for this
----------------
One other thing to consider, is the clearance at the head of the case vs the chamber
there should be minimum of .002" clearance, preferrably .003-.004"
not all sizing dies squeeze down this area behind the .200" line is why
A correct dia straight wall pistol sizing die can accomplish sizing this area if FL rifle dies wont
Maybe a .50 cal variant or something will work for this
I have used pistol dies to squeeze down the head slightly for some cases
My 284 brass measures between .495-.498 at the head (not rim)
but can expand to .500" if loaded hot so needs to be squeezed down somehow
When I had my first custom reamer made by Manson I spec'ed out .500" at the head ....
..."Thinking" that things may not always cut perfectly, that when I cut the chamber I would allow for a non perfect setup, side pressure on the reamer etc, to slightly cut an oversize chamber...to maybe .501"
so I spec'd out the reamer to be slightly tight but still with brass clearance thinking I would compensate for possibly cutting oversize
but Nope, it cuts the chamber true to size at .500" which bit me and is too tight
So after cutting a chamber I have to also enlarge the chamber in the head area another .001" to .002" or else I get clickers and stuck cases.
So you also could check the dimension of your chamber in the head area to be sure it has enough clearance.

Great info. Thank you sir.