OzFclass

RDavies wrote:Yes, I had chronographed loads not long before and was around 2820 fps. I suspect that the velocity had likely gone up due to the usual new barrel, 150 round velocity jump. I have been using the same batch of powder for the last 2 years in previous barrels.
I normally use the PMC primers which are slightly bigger, but was saving them until I had got a load pretty much dialed in and velocity jump out of the way. Even so, I would not have expected the BR2s to be so loose.

Rod,
PMC primers are far softer,power wise,than any of the usual primers we use.As I understand it the idea is a softer primer gives less pressure than a conventual primers,so you can add more powder to a PMC primed load and end up with more velocity at the same pressure .I started to try this with Match Rifle loads but did not complete the tests.It was obvious however that the PMC primers gave a lot less velocity for a given powder charge than when my usual primers ,Federal GM215 M,were used.
Mike.

In the 284 with 2209, switching from BR2 to PMC primers, I only have to go up about 0.2gn to keep the same speed/tune. I usually switch over to the rarer PMC primers once the barrel has gone through its velocity increase after 150 rounds or so. I don't use magnum primers in my 284, but am about to do some crony testing between CCI250s/CCI BR2 and Fed 215s in my bigger 7mm/300WSM.
I,m hoping that using the milder PMC primers like you said will help me to keep the same speed/tune, with less pressure. Some people complain the PMCS are too hard to seat. In the softer cases, they might be just what we want.

most large rifle primers measure .210 plus or minus a few tenths, but some i have measured run from .209 to .211+ and can be oval shaped as well. (possibly, the number of anvils being a major influence on roundness).

small rifle primers may also vary significantly in diameter and roundness, the old rem 7.5 (twin anvil) being a good example of an oval primer.

all of the above factors can effect primer seating feel and the strength of the interference fit created between the primer and primer pocket.

cheers
dave

RDavies wrote:In the 284 with 2209, switching from BR2 to PMC primers, I only have to go up about 0.2gn to keep the same speed/tune. I usually switch over to the rarer PMC primers once the barrel has gone through its velocity increase after 150 rounds or so. I don't use magnum primers in my 284, but am about to do some crony testing between CCI250s/CCI BR2 and Fed 215s in my bigger 7mm/300WSM.
I,m hoping that using the milder PMC primers like you said will help me to keep the same speed/tune, with less pressure. Some people complain the PMCS are too hard to seat. In the softer cases, they might be just what we want.

I seat primers with an old Super Simplex press,no trouble,however I believe you need to be lucky with the shellholder you are using,in the small rifle I have two shellholders,one distorts the primers every time unless the primer pocket is extremely loose,the other will seat primers perfectly every time,even if they are tight military cases.
With large rifle primers i have loaded .303 and .308 cases without any troubles.
In the .308 with 208 grain A Maxes moly coated there is 72 feet per second difference in an identical powder load,between Federal GM215M and PMC primers.
Mike.

Mike,

The only comparison I have is between BR2 & PMC back some time with molied 210 SMKs backed by VV N550, also in a .308 case. The PMCs ran to an average of 6 fps faster than the BR2s with the same load.

Interesting that a change of brisance will do different things depending on the powder being used. My guess is that you were lighting up AR2209, Mike.

John

johnk wrote:Mike,

The only comparison I have is between BR2 & PMC back some time with molied 210 SMKs backed by VV N550, also in a .308 case. The PMCs ran to an average of 6 fps faster than the BR2s with the same load.

Interesting that a change of brisance will do different things depending on the powder being used. My guess is that you were lighting up AR2209, Mike.

John

It was 2209 John.

I put Fed GM 210 match primers in 100 brand new unfired cases yesterday, and they were worryingly "loose". They wont fall out just yet, but they sure as hell werent tight.
These were the same cases that I advised Matt P that I had measured, as he was chasing unfired case dimensions....at 0.406" in the extractor groove itself, and 0.498" immediately above the groove and on the very thickest part of the case.
Rgds
Tony

ecomeat wrote:I put Fed GM 210 match primers in 100 brand new unfired cases yesterday, and they were worryingly "loose". They wont fall out just yet, but they sure as hell werent tight.
These were the same cases that I advised Matt P that I had measured, as he was chasing unfired case dimensions....at 0.406" in the extractor groove itself, and 0.498" immediately above the groove and on the very thickest part of the case.
Rgds
Tony

Tony,

I think Matt was asking about Winchester (brand) 284 brass. Is that what you have?

Alan

whooops...no, mine are all Lapua necked up

Back to the loose lapua brass, what is the lot number Tony?

Cuting in here with similr issues with another cal (.308).

After reading this thread I am starting to wonder if there is not some problems accross the board with Lapua brass, perhaps they have changed their recipe, or their QA has dropped.

I dont feel a though what I am doing is an overly HOT load and I am experiencing loose primer pockets also, the thing is, it seems random, I can shoot a string of 20 with the load without an issue, then the next string I will back out maybe 2 or 3 primers.

I am going to give winchester brass a run with it.

I did try some older Lapua brass I had without issues, but I need to buy new brass.

I wonder just what is going on with Lapua.

Just on the QA thing, I have had several cases with creases in the necks from new, the creases look like an issue from when they were cast/formed, me been me they went straight in the bin, maybe I should have kept them

Far out if its happening with 308 that is a worry! Would like to know the load.

AlanF wrote:Back to the loose lapua brass, what is the lot number Tony?

Alan,
These latest "loose" ones are Lot P00620601

My first 300, which are behaving themselves after 2-3 firings, are Lot P00577401
Rgds
Tony

ecomeat wrote:

AlanF wrote:Back to the loose lapua brass, what is the lot number Tony?

Alan,
These latest "loose" ones are Lot P00620601

My first 300, which are behaving themselves after 2-3 firings, are Lot P00577401
Rgds
Tony

I have 400 from that lot ! However, they don't seem to be a problem with BR-2s primed new, and don't seem to be any bigger than an older Lot No that have been okay for several firings. Hmm. Don't know....

This has got me worried. I'm going to do some testing in the morning, testing identical loads with 180gn VLDs with older P00532501 and newer P00620601. I notice the latter is the same as Rod Davies reported problems with.

Alan