284W & Primer Pockets

[ThunderDownUnder]

The 284W and the 284 Shehane that I am using are great long range F-Class calibers with the heavy 180gr, 7mm projectiles. I am using necked up 6.5x284 Lapua brass and the accuracy is exceptional, BUT, (aint there always a but) the primer pockets expand a little too readily.

I'm using AR2213SC powder (Hodgdon H4831) and have found when using loads that give 2920+fps with 180gr projectiles that the primer pockets loosen up pretty quickly. I have taken to case forming with my 284S by using 162gr Amax and launching them at 2900fps. This fire forms the case nicely and gives me an accurate first fire round I can use in competition out to 600 yards. The pockets stay tight with this gentle fire forming routine and loosen up more progressively once loaded with the 180 grainers.

At longer ranges I use the 180s launched at approx 2950fps and this really starts to expand the primer pockets. It seems the 284W case when coupled with the heavy 180 grainers shows no signs of excessive pressure except at the primer pocket. I'm guessing the 180s are pushing the case design for these heavy bullets at 2900+fps velocity. Accuracy is so good I'm willing to suffer case life of only 6-10 firings but I'm curious about what other shooters are finding the case life to be with 180gr projectiles?

Ian

 

[GLC]

Hi Ian
My 7/270 wsm is hard on primer pockets,my load is def not over pressure velocity is around 3050-3080 5 firings and they are very loose, I purchased a hart primer pocket swager and this did actually tighter the pockets, so I reckon I can get another firing at least.
Unfortunatly I think it's the price you pay! at least you have less cost with the .284 and you are getting magnum performance.
Rgds
Gary

 

[Travelor]

You do not say how much powder you are using, but I did a quick and dirty check on QuickLoad using a Berger 180 gr bullet and a 30" barrel and I would suspect around 56 grains. The pressures you are getting are probably in excess of 62,000 psi and that is too hot.

I think you would be better served in backing off your load and saving your brass.

Just my thoughts,

George

 

[oldroper]

The 284W and the 284 Shehane that I am using are great long range F-Class calibers with the heavy 180gr, 7mm projectiles. I am using necked up 6.5x284 Lapua brass and the accuracy is exceptional, BUT, (aint there always a but) the primer pockets expand a little too readily.

I'm using AR2213SC powder (Hodgdon H4831) and have found when using loads that give 2920+fps with 180gr projectiles that the primer pockets loosen up pretty quickly. I have taken to case forming with my 284S by using 162gr Amax and launching them at 2900fps. This fire forms the case nicely and gives me an accurate first fire round I can use in competition out to 600 yards. The pockets stay tight with this gentle fire forming routine and loosen up more progressively once loaded with the 180 grainers.

At longer ranges I use the 180s launched at approx 2950fps and this really starts to expand the primer pockets. It seems the 284W case when coupled with the heavy 180 grainers shows no signs of excessive pressure except at the primer pocket. I'm guessing the 180s are pushing the case design for these heavy bullets at 2900+fps velocity. Accuracy is so good I'm willing to suffer case life of only 6-10 firings but I'm curious about what other shooters are finding the case life to be with 180gr projectiles?

Ian

Have you read about this rifle that uses 56gr/H-4831 and how he developed his loads?
http://www.6mmbr.com/gunweek088.html

 

[ThunderDownUnder]

It always risky giving loads on forums but if you are interested here is what I am using in my 284 Shehane case. These loads are all with AR2213SC (Hodgdon 4831) powder and standard CCI primers.

180gr Berger VLDs at 58gr of powder for 2940fps (ES = 5, SD= 2.2) This loosens primer pockets and is also my favorite target load.

180gr Berger VLDs at 57.5gr of powder for 2910fps. Not so bad on primer pockets and good accuracy.

162gr Hornady Amax's at 57gr of powder for 2960fps. Not so bad on primer pockets and good accuracy.

162gr Hornady Amax's at 57.5gr of powder for 2995fps. Not so bad on primer pockets and good accuracy.

All the loads with 180gr projectiles jammed and launched at 2900+fps expand the primer pockets. The 162gr Amax projectiles jumped and launched out at 2960+fps are milder on the pockets as you would expect. The thing is on the longer ranges, 600+ yards, the 180 grain bullets are the only option if you want to be competitive.

I now mix and match my projectiles to maximise primer pocket life span and use the Hornady Amax's out to 600 yards and the Berger VLDs at the longer ranges.

Ian

 

[RDavies]

I thought of going to the 284 Shehane to get the magical 2950 fps which I hear so many people getting with their 284 Shehanes. But when I plug it into Quickload , to get 2940 fps, with bullets jammed and 58gns of 2213sc, I get over 72500 psi.
With 168gn bullets the pressure is ONLY 64000 psi.
I have tried the higher node with a few barrels, but less consistancy, hard bolt lift, expanded primers, swollen bases and ejector marks protruding quite a way has always made me revert back to the low node.

As for being competitive. I remember one Queens Prize shoot at Belmont where about 10 shooters were using 284s.
The first 3 place getters were loading to 2800 fps, while all the back runners were loading to 2920+ fps and getting less consistancy, more verticle on our smaller targets.

 

[ThunderDownUnder]

cr500, I take it you are using a straight 284W case? The 284W case gets pressure signs a little earlier than the 284S but still can get 2960fps with 2213SC powder. I wouldn't put too much value on your use of QuickLoad and the pressures it suggests, unless you plug in all the other variables for the chamber size, powder burn rate and bullet seating depth , etc, etc. I have Quickload too and at best it gives a rough approximation of real world outcomes.

As for pressure signs on my 284S cases there aren't any of the usual suspects present only primer pocket expansion and probably because its a magnum size case with a 308W size head. The 180gr VLDs still shoot well at 2800fps but come on down to South Australia's state rifle range range and shoot in our very windy and changeable conditions and tell me again about the losers running the higher velocities. Its not about bullet drop its all about bullet drift in windy conditions.

What velocities and projectiles are you using and what are your primer pockets doing?

Ian

 

[RDavies]

Ian. I am using 168 Bergers and 175 sierras in my 284 and primer pockets are fine. I have about 20 shots through each of my 150 cases for my current barrel. I have used 1 each of True-flite, Maddco, Broughton and Tobler barrels and got around 20 firings out of each case, except for my tight true flite, which even showed pressure at 2820 fps (2209 powder)which is where all of my barrels have prefered it. As you say though, I dont usualy shoot places as windy as Lower Light (Yet), so accuraccy is more of a concern for me than wind bucking.
I usualy save a few cases for load developement when trying to get to the 2950 fps node and these have lasted 2 shots until the primer was loose and the extractor hole was getting smeared. As you say though, my chamber is not blown out as much as some and my throat is probably shorter.
Maybe Moly or HBN might help get that last little bit out of it.
RodD

 

[RossL]

Regarding primer pockets....I read an article in Precision Shooting several years ago titled: Make mine a 6mm-284.

In the article the author also had primer pocket issues. He thought his loads/pressure were not excessive but he had short brass life due to loose primer pockets. He solved the issue by having the reamer's base reground smaller so there was less expansion and it solved his problem.

Unfortunately I cannot make other comments on what he did for sizing if there were issues or not. All I remember is the smaller reamer dimension.......

 

[kyreloader]

I also shoot a .284 Shehane with H4831 and 180g Bergers. My velocities are almost identical to the above poster. 58g of H4831SC chonographs at 2940 with SDs of single digits. I do not however have any problems with my primer pockets. I have shot these particular cases for 6 reloads (annealed after 3) and I have tight pockets on all my cases.

Did you get a bad lot of cases? (Hard to believe if Lapua).

 

[ThunderDownUnder]

It could well be a bad batch of cases. I have bought another 100 lapua cases and expanded the necks and trimmed the length, so I guess I will have to wait and see how they perform. I'm fire forming with 162 gr Amax's so its a gentle break in before the 180s and 2940fps.

Ian