Case Dimensions 338Wm

[truck driver]

While working up so new loads for my .338Wm the question of case cap has been mention as possibly being high and I have weighed the once fired cases several times and double checked my scale with several different calibration check weights to assure that all was equal. The H2O cap for the batch of Nosler brass seconds I have is 91.5-92.0grs. Giving that all chambers are not reamed equally I assumed mine was a little over size.
My velocities are lower than expected which could be contributed to the larger than average H20 cap.
I decided to measure some cases and all I have are Nosler seconds so it is what it is.
New unfired virgin brass measurements are ( .528" rim dia, .529" belt dia, .508" web dia, .489" shoulder dia, .362" neck OD, .335" neck Id, 2.483" OAL.)
Multi fired and annealed once and sized brass in my Reading dies (rim dia .528", belt dia .529", web dia .513", shoulder dia .490", neck OD .361", Neck Id .335", OAL 2.491")
Multi fired annealed once unsized ( rim dia .528", belt dia.529", web dia .513", shoulder dia .429", neck OD .370", neck Id.345", OAL 2.489") The case neck thickness is .014".

My new brass is under Saami specs by a few thousandths here and there which to me is no big deal and my sized brass is also with in a few thousandths.
Where the difference really comes out is the H20 cap which is 6grs-4grs more than Saami's 86grs-88grs.
I have to use 5grs more powder to reach printed velocities. I thought maybe I would be chasing the dragons tail with over pressure loads but my primer pockets are still the same dia as the new virgin brass so I have seen no pressure signs.
Before some says you have a slow lot of powder I have seen this with different brands of powder in or around the same burn rate.
Are my case dimensions normal or should I think about getting new brass? I don't want to get caught flat footed when the brass wears out and find that there is a big difference in H2O cap with the new stuff and have to rework everything. I realize there will be a difference between lots of brass but just how much difference can I expect?
I can get Norma brass in 100pc lots and that would give me piece of mind where I can use 25pcs for load development and still have enough for hunting loads.

 

[truck driver]

I just got off the Saami web site checking the specs for the 338Wm and except for the rim and belt diameter of my fired brass measurements are right on the Saami drawing figures for the chamber dimensions so the Nosler brass must be lighter than other brands causing the increase in case capacity.
Think I'll pick up some Norma brass for my Montana trip just for piece of mind since I was having extraction problems with the smaller Nosler rim jumping out of the extractor claw before the brass was fully extracted when not firmly extracting the cases at the bench.

 

[Divernhunter]

I loaded and shot the exact load in Nosler, Win and Hornady brass. I now know why my groups were not real good with mixed brass loads. Once I sorted and shot groups of same brass the results were a bit surprising. The Nosler shot best and had an SD2 but about 75fps lower that the fastest load. Win brass shot to a different spot and were middle speed and SD. Hornady brass shot the highest speed and SD and grouped into another spot. Nosler gave the best group. That is what I am taking to Africa in spite of less speed. I really do not think it will matter to the animals. I had similar results with the 3 different brands of brass in my 257W. By mix and match of brass I have 100grTTSX and 120gr Swift A-Frames shooting to almost the same point. The 257W will also be going to Africa.

 

[SJB358]

I think you're fine TD. I can't see any problems with using Norma, Nosler or whatever you like. Mike always said it best in that any single change of component can change stuff quite a lot. I use a bunch of Winchester and Nosler brass and work up in each brass for different Bullets.

Seems like everything is going well with your rifle. I imagine you'll be getting your hunting load pretty quick.

 

[truck driver]

I think you're fine TD. I can't see any problems with using Norma, Nosler or whatever you like. Mike always said it best in that any single change of component can change stuff quite a lot. I use a bunch of Winchester and Nosler brass and work up in each brass for different Bullets.

Seems like everything is going well with your rifle. I imagine you'll be getting your hunting load pretty quick.

If we get a break from this monsoon season and I can get to the range to finalize my loads it will be nice.
I have been able to get good groups and consistent velocity with Nosler brass but I'm wondering about the smaller than Saami specs for the rim diameter and belt diameter which can cause malfunction and cycling problems.

 

[Partisan]

I have a batch of Nosler 338 brass and a sample of 5 averages 90.4 grs H2O.
A batch of Hornady comes in at 88.9...
A batch of Norma I haven't water tested but weighing the dry fired cases puts it roughly between the Nosler and Hornady...
For what it's worth.

 

[truck driver]

I have a batch of Nosler 338 brass and a sample of 5 averages 90.4 grs H2O.
A batch of Hornady comes in at 88.9...
A batch of Norma I haven't water tested but weighing the dry fired cases puts it roughly between the Nosler and Hornady...
For what it's worth.

Thanks for the info that's what I was looking for to see if others are seeing larger H2O caps with Nosler brass since they are having it made on the Silver State machines they bought. When Norma was making it it was a lot different.
My brass is running a grain to a grain and a half more H2O cap then what yours is and it has been confusing as to why my velocities were slower, More capacity less pressure so that makes senses.

What are the rim and belt diameter on the 3 brands you have?

 

[SJB358]

TD, don't take the wrong way, but 1-1.5 grains overall H20 capacity wouldn't be as noticeable as a different throat, somewhat larger chamber or a host of other things. Even QL will only show so much difference when you alter the case capacity. A tight/loose Bore, slow/fast Lot of powder, different primers seem to make more difference than brass most of the time. I'm not saying it doesn't change the factors at all, but between WW and Nosler brass I've seen as much as 5 grains or more difference in overall capacity and used the same loads in a few different powders. You couldn't tell the difference in speeds over multiple trips to the range and chrono sessions. Now, change the lot of powder or change the rifle itself and it changes dramatically.

My only concern for you is feeding. Seems weird a couple thousandths are affecting your feeding that much. Usually a Ruger is like a junkyard dog and devours just about everything.

I will measure some of my stuff and see what I get but again, the old Alaskan seems to feed like a hound sucking down sausages.

 

[truck driver]

Scotty I don't take anything the wrong way unless it is presented to me wrong so there is no problem and this is a learning process for me since I'm unfamiliar with magnum cartridges and all comments from you are welcome.
The Ruger feeds great it's just that if I don't firmly extract the cases after firing they drop out of the extractor claw before they completely clear the chamber when loaded singly at the range like a single shot. Pull the bolt back hard and they go flying. Could be I need a new extractor claw.

 

[SJB358]

I wouldn't worry too much. My 70's will do the same thing here and there if you cycle real slow. They get pushed a little by the ejector and don't have enough to clear the receiver.

 

[truck driver]

My 70's don't do that since they both have a M16 style claw. They catch the front of the magazine follower and pop out of the claw when extracted slowly.

 

[SJB358]

I was talking about mine with the full length extractor.

 

[truck driver]

I was talking about mine with the full length extractor.

Yeah okay I understand. The Ruger also has the full length extractor but acts like a push feed except it doesn't hold the cartridge as tight as my M70s. The magazine follower can cause a lot of feeding and extraction problems and had to put a metal one in the 7RM so it wouldn't jam. Maybe a little polish job will take care of it since it has the mat finish on it also.

 

[SJB358]

I was talking about mine with the full length extractor.

Yeah okay I understand. The Ruger also has the full length extractor but acts like a push feed except it doesn't hold the cartridge as tight as my M70s. The magazine follower can cause a lot of feeding and extraction problems and had to put a metal one in the 7RM so it wouldn't jam. Maybe a little polish job will take care of it since it has the mat finish on it also.

Could be. My Rugers are very rough and take some shooting or polishing to get them smooth. I tend to just try and shoot them a bunch.

Your rifle should act as a CRF, meaning it picks up a round out of the magazine and has full control of it, in and out of the chamber, if it doesn't do that, I'd contact Ruger and let them check it out.

 

[truck driver]

It does feed like a CRF or you can just lay a round in the action and chamber it like a push feed since the claw slips over the rim very easily. My CRPF M70 takes some doing to load like a push feed and prefers the cartridge in the magazine for feeding and works as slick as snot.
I'll just get out the dremil tool and a buffing wheel and slick the follower up some.