308 Small Primer Brass - Ignition problem - Solution Found

[Keith Glasscock]

I've got a quandary to solve.

308 Win "practice rifle" - 1200 down the tube.
Lapua Palma Brass 5x fired, bumped .001"
Wolf SRM Primers
Varget
Lapua 167 Scenar Bullets jammed .015"

Here is the problem:

This thing is a hammer. Sometimes I wonder if it isn't tighter shooting than my F-open rifle, but I digress.

One to three out of 60 shots will fall low. I have always assumed they were because of me "it is a practice rifle for a reason." That is, until I was shooting with the Labradar the other day. Lo, and behold, the low shots are leaving 40 fps slower than the rest. I've always had mediocre ES during load development on this thing, but these are different. They recoil less, they sound funny.

I tried a couple of experiments already:

A little more primer crush up to .005" - Nope.
Use a different bolt and firing pin - Nope.
Change the charge upward/downward - Nope.
Tried different bullets (185 Jugg) - Nope.

So, I'm to the point where I think it is the primer, or the way I seat them. I'm using a 21st century hand primer. I've tried seating by feel alone, no difference. I've tried using the hard stop with various crush numbers to no avail.

I have CCI 450 primers on hand, and Federal 205's (not M's). Since small rifle primers seem to have evaporated from the world, which would you try first?

Thanks in advance,

 

[mgunderson]

What action?

 

[TAJ45]

The other bolt as well as this one: when was the f pin spring last changed out?
It was new info for me when "I read it here" a year, prob 2 or so back, of a fellow chasing everything he and guys here could think of when a new spring was installed, VOILA!

 

[Dusty Stevens]

I have never been a fan of the small primer in the 243/308 case. I believe tubb tested it and came to the same conclusion- use lrp

 

[LVLAaron]

I've never had any trouble with CCI450's and Varget in SRP configuration. That's in 223/6.5cm/308.

Maybe embiggen the flash hole?

 

[riflewoman]

Primer selection and ambient temperature are key.

https://www.youtube.com/playlist?list=PLTTrjvDib94m9twQ7mD937yNMOT-7JQEy

after you finish these 5 videos you’ll get the idea. The Wolf SR primers are a bit soft. Rem 7-1/2 and other hotter primers are better.

 

[TAJ45]

Wolf SR (labeled .223Rem) are not the Wolfies to use.
Wolf labeled 5.56 are the SRMag and are quite up to the task. It was a while before i stumbled onto that bit of info.

 

[dcali]

I use 205s in my .308, and get very reliable velocity with varget and bullets between 185 and 215 in temperatures between 30 F and 100 F.

I’m guessing it’s the primers, or maybe something is amiss in the action? Something binding somewhere?

 

[Straightshooter1]

Aaahhh, just in time for an issue I too am having with my first use of .308 Lapua Palma cases. I thought I'd try some and see how they worked out in my RPR with a 24" Krieger barrel mounted.

As I kinda anticipated, I found some cratering as I feel I'm going to need to bush the firing pin to avoid this. I accidentally bough some CCI 400's when I meant to get 450's. So I went back to the store and picked up some 450's and loaded up some of both to test using 44.0 gr. of 4064 behind 168 SMK's. Primer's were seated with a .003 crush.

So Saturday I fired 10 rounds of each and both primers performed pretty well. The cartridges with the 400's gave me a SD of 6.4, and ES of 18 and on a somewhat windy day I managed a .510 group. The 450's gave me an SD of 7.3, an ES of 25 with a .585 MOA group. Given that the cases are new with no case prep other that some lube for seating, the results surprised me.




The odd thing though was that I expected the magnum primers to produce more velocity that the other and it turned out the other way around. The average velocity for the 450's was 2684 fps and the 400's was 2717 fps. I'm going to run another test just like it and see if I get the same results. Shouldn't the magnum primer's produce higher velocities?

One other question . . .

I bought an RCBS small primer uniformer and I found that it was difficult to get it into the pocket, so I didn't force it and decided to take a bunch of measurements. The uniformer bit is .173" in diameter and the Lapua cases have pockets that are .172 in diameter. The number I've read as a "minimum" for small primer pockets is .173, so the uniformer is good for that, BUT . . . I'm wondering if I can find a tool that would better fit the Lapua primer pockets or would enlarging the pocket by .001 be of any concern (as in making sure the pockets stay tight over time)?

 

[Straightshooter1]

So, I'm to the point where I think it is the primer, or the way I seat them. I'm using a 21st century hand primer. I've tried seating by feel alone, no difference. I've tried using the hard stop with various crush numbers to no avail.

I have CCI 450 primers on hand, and Federal 205's (not M's). Since small rifle primers seem to have evaporated from the world, which would you try first?

I really don't have any experience with small rifle primers, but have read a lot about them. I suspect it likely that it's something about those particular primers. Since you have both Federal and CCI primers, it's probably a good idea to go with the CCI primers since they are thicker cups than the Federal (e.g. .025" vs .0225"). Then, if you still have the same problem, you'll have to look at something other than the primer itself.

 

[Ned Ludd]

FWIW - I've always had very good results with straight Fed 205s (not Ms). I don't use anything else unless I have to. However, in the past I have directly compared the Fed 205s to CCI 450s and Russian 556s using a .223 Rem load with 90 VLDs over H4895. Using my standard load (i.e. loaded identically except for the primers), both the CCI 450s and the Russian primers gave approximately 25 to 30 fps greater velocity than the Fed 205s, so my guess is that they have slightly greater brisance.

Have you weighed the cases that exhibit low velocity, or determined their water volume? 40 fps velocity variance seems like an awful lot for it to be a solely an issue of case volume, but it's pretty easy to check. Weighing the primers themselves is another thing you could do before loading/firing to see if the amount of priming compound might be a contributing factor. Again, 40 fps seems like a lot for it to be caused solely by the amount of priming compound, but it's easy enough to test one time. Bart here on the forum has suggested that it is not uncommon for a piece of brass that gives unacceptable velocity variance from the mean to continue to do so upon repeated firings. It might also be worth checking to see whether it might be due to specific pieces of brass, if you haven't already.

The only other thing I can think of may be viewed as a little far out there, but it happened to me, so here goes. I normally tap the bottom of each case three times on the reloading tray after dispensing each charge, just to settle the powder down into the case a bit. Yesterday, I made a mistake and had to re-weigh the powder in three cases (.308 Lapua Palma brass), because my thoughts wandered while weighing the original charge and I loaded them to the wrong charge weight. In one of the three cases, a kernel of powder (H4895) had actually become lodged sideways in the flash hole, possibly due to my tapping the cases to settle the powder. As a result, I had to tap the case mouth pretty hard to get the lodged kernel to come out again to be re-weighed. Afterward, I got to thinking about that. I can imagine that having a kernel of powder jammed down in the flash hole might effectively diminish the brisance of the primer, thereby leading to poor ignition. I have no idea how often this actually happens, because I rarely make such a mistake and have to empty the case to re-weigh the powder. Anyhow, it's just a thought.

 

[NV_Dmax]

Did you set those cases, that gave wacky velocities, aside and examine them closely? Maybe something inside like a lot less case volume or obstructed flash hole? Ignition system on the rifle tuned and fresh? (I had a Panda that did that and when I get the correct trigger hanger the random low velocities went away)

 

[1shot]

Having experienced this myself, I think the problem is the primers. I use 450's exclusivly in my SP Alpha and Peterson brass. If that doesn't solve the problem, which I think it will, put in a fresh FP spring.
i hope this helps,

Lloyd

 

[J F Johannes]

Keith, When I read your post I just about rolled out of my chair laughing. Do you remember us having this same conversation at Cascade in March about my FTR gun? I said, "this palma brass is not getting good ignition when it is cold, I can feel it in the gun". We talked a little bit and then you mentioned that sometimes you can "hit" a primer too hard! Well that got me thinking and I didn't want to ditch the palma brass just yet. In the summertime this gun was hammering and when the weather started to get colder it fell apart. Then COVID19 happened pause...........So I finally got to testing again last week. I have had since day one with this palma brass, trouble getting primers to set below flush and a lot of people here on AS said that you did not need to uniform pockets in this brass, so I didn't. Well I ordered a uniformer from KMS and proceeded to uniform a couple dozen cases and it freaked me out how much brass came out so I only did a few. Now the primers sit at .006 below case head. So I loaded up the same load as I had been using and shot them over the chrono in 42 degree weather. The velocity went up 30 fps and it was back to hammering one hole groups at 200 yds. The ES was 7 and the SD was 3. This gun never shot so good. This Saturday I will load up some of each(uniformed/not uniformed) with the same load and see what happens. I don't know if that is your problem, but sure seems to be mine. Thanks for the help.

BTW: BR-4 primers, Varget, Lapua SRP, Berger 200.20x in a Surgeon 591 action.

Jim

 

[Liven The Dream]

I've got a quandary to solve.

308 Win "practice rifle" - 1200 down the tube.
Lapua Palma Brass 5x fired, bumped .001"
Wolf SRM Primers
Varget
Lapua 167 Scenar Bullets jammed .015"

Here is the problem:

This thing is a hammer. Sometimes I wonder if it isn't tighter shooting than my F-open rifle, but I digress.

One to three out of 60 shots will fall low. I have always assumed they were because of me "it is a practice rifle for a reason." That is, until I was shooting with the Labradar the other day. Lo, and behold, the low shots are leaving 40 fps slower than the rest. I've always had mediocre ES during load development on this thing, but these are different. They recoil less, they sound funny.

I tried a couple of experiments already:

A little more primer crush up to .005" - Nope.
Use a different bolt and firing pin - Nope.
Change the charge upward/downward - Nope.
Tried different bullets (185 Jugg) - Nope.

So, I'm to the point where I think it is the primer, or the way I seat them. I'm using a 21st century hand primer. I've tried seating by feel alone, no difference. I've tried using the hard stop with various crush numbers to no avail.

I have CCI 450 primers on hand, and Federal 205's (not M's). Since small rifle primers seem to have evaporated from the world, which would you try first?

Thanks in advance,

Had the same thing with Wolf SRM in .308 Peterson Brass ? I was telling my freind Mr. Spiker and He said they don't seem to work for that Application.
I switched to CCI 450m and have not looked back.
The Wolfs never fail in my AR ???

Went to the Shop had fail to fire in my 6MM Norma Dasher with Wolf SRM also

 

[savageshooter86]

BR4 or 450s. Although I never had issues with my Wolf or Tula primers in my Lapua palma brass. That was a Savage target action

 

[memilanuk]

Most of the likely suspects have been mentioned already... firing pin spring age, ambient temperature, any kind of lube(grease) on the firing pin (particularly in dusty and/or cold conditions), the occasional poor primer seating, and primer brand/model/lot#. I've had one lot # of a particular primer shoot great, and the next shot horribly. Still good groups up close, but with SD/ES going from 4/10 to 18/44 didn't do anything good for vertical (or scores) down range.

Personally, if you're reasonably certain that the mechanical issues have been addressed, I'd start sub'ing primers until you find one that shoots well with good SD/ES over a reasonable sample size.

 

[Bob3700]

if u go back to when Remington made their 308 BR brass ( made w/sr primers) folks reported ignition issues at temps below 40 some odd degrees. Dont know why that would change with todays components. The wt of powder in a 308 case is maxing out what a SR primer can ignite. In warm weather they are excellent, cold weather - not so much. Some switched to Rem 71/2 's as they are some of the hottest SR pRimers out there.

The old Wolff SRM's and the CCI 41's seem to be interchangable in my Lapua 308 SR cases. Same accuracy n performance.

Unless u shoot in biathalon conditions, the SRM brass works great.

I would id the cases that produce low shots and cull them out. Then shooe that same batch of cases and see if the low shots still appear. If they do, u know it is not the brass and can elimanite them in ur quest for the problem.

 

[Kurz]

I have had since day one with this palma brass, trouble getting primers to set below flush and a lot of people here on AS said that you did not need to uniform pockets in this brass, so I didn't. Well I ordered a uniformer from KMS and proceeded to uniform a couple dozen cases and it freaked me out how much brass came out so I only did a few. Now the primers sit at .006 below case head. So I loaded up the same load as I had been using and shot them over the chrono in 42 degree weather. The velocity went up 30 fps and it was back to hammering one hole groups at 200 yds. The ES was 7 and the SD was 3.

It freaked me out the first time as well until I asked around and got the answers that indeed the Lapua brass came with primer pockets smaller than average. So I got right with it and uniformed all of the brass I was using currently. Now I just don't buy the Lapua brass any more...

Try the test and see what you get for results.

 

[Papa Charlie]

Keith, When I read your post I just about rolled out of my chair laughing. Do you remember us having this same conversation at Cascade in March about my FTR gun? I said, "this palma brass is not getting good ignition when it is cold, I can feel it in the gun". We talked a little bit and then you mentioned that sometimes you can "hit" a primer too hard! Well that got me thinking and I didn't want to ditch the palma brass just yet. In the summertime this gun was hammering and when the weather started to get colder it fell apart. Then COVID19 happened pause...........So I finally got to testing again last week. I have had since day one with this palma brass, trouble getting primers to set below flush and a lot of people here on AS said that you did not need to uniform pockets in this brass, so I didn't. Well I ordered a uniformer from KMS and proceeded to uniform a couple dozen cases and it freaked me out how much brass came out so I only did a few. Now the primers sit at .006 below case head. So I loaded up the same load as I had been using and shot them over the chrono in 42 degree weather. The velocity went up 30 fps and it was back to hammering one hole groups at 200 yds. The ES was 7 and the SD was 3. This gun never shot so good. This Saturday I will load up some of each(uniformed/not uniformed) with the same load and see what happens. I don't know if that is your problem, but sure seems to be mine. Thanks for the help.

BTW: BR-4 primers, Varget, Lapua SRP, Berger 200.20x in a Surgeon 591 action.

Jim

I had the same issue with my .308 Win Lapua large primer cases. Had trouble seating some primers and some the pocket was too tight to install the primer at all. I had to uniform all my brass. Once I do, I am able to seat everything with ease and to the same depth using the Bald Eagle priming tool.
As for the issue that Keith and Jim are describing, I have never had that issue with variations in temperature. But I went with the large primers because from some articles I read it seemed to indicate that the Small Primer was at its limit for the .308 case volume.
As for the issue with large primer pockets weakening the case, I have cases that have 27 firings on and the pockets are still tight.

I don't know if any of this really has the potential to cause Keith's problem, but interesting none the less.