Small primer brass vs traditional large primer versions.

[PracticalTactical]

I’m curious what your opinion is on these small primer cases vs the traditional large primer versions.

Take for example the 308 cases from Lapua with a small primer… I get that because guys in FTR F Class or even a PRS shooter in Tactical division wants to run at higher pressures with better brass life. It's not for me, but they have no choice because it has to be a 308.

But what really sends me into a tailspin is rounds like the 6 Creed in small primer… or 6.5x47L or 6x47L… I just don’t see the benefit.

If a 6x47L guy wants more speed then he should just build a 6 Creed.

But why on earth would a 6 creed guy want a small primer… to what run even faster?

And all this at the risk of weak ignition, hang fires and wild velocity in cooler weather.

Now, I’m not throwing this out of my butt… 10 years ago I blew 300 rounds trying to develop a load for my 6x47L in January and got hang fires and velocity spreads that were all over the map. Eventually I started forming cases from 6XC brass to get the large primer and everything settled down to single digit ES… and all was well ever since.

 

[FUNCTIONAL]

The claim is small rifle primer pockets hold up better than large at the higher pressures...ie longer brass life.

I run small in my 6.5x47, never an issue in any temp/weather. I run large in my 308 and my previous 6creeds, also no issues. I'd bet your issues may have been primer seating or maybe bad primers. My buddy runs nothing but 6x47 over multiple barrels and never had an issue with hang fires or velocity/sd/es spreads.

 

[PracticalTactical]

Functional, Have you ever tried forming cases for your 6.5x47L using large primer brass and compared the results to small primers?

I get what the Lapua brochure "claims" but question if proponents and defenders of the small primer thing have actually done any structured chronograph testing to substantiate the advantage claims over an extended period of time and actually compared small primers to large in side by side tests like I have.

From my discussions here and there it seems that most guys just say its more accurate but with no evidence either way...

And more accurate is not to be found on target... it would be evident on the chronograph with lower ES.

There was surly nothing wrong with anything during my own tests as I tested a broad range of primers and powders over several weeks... the only constant was cold mid winter weather during load development.

If such a temperature change is the deciding factor between great and unacceptable... well it has me dismissing the small primers on that basis alone.

I also discussed this problem at that time with David Tubbs throughout the development period and he discussed it with Boots Obermyer and between them agreed that trying to light 38 plus grains of powder with a small primer was a bad idea... yet the practice persists.

 

[FUNCTIONAL]

I havent because it worked so well in all of my seasons I had no need to mess with it. I dont believe one is more accurate than the other at all either, that in my opinion is more dependent on case design. I dont have any hard or fast rule but I wouldnt use small primers on "larger" capacity cartridges like the creedmoors, 260/243, 308 (actually chose large primer over small in my recent buy) and in lesser volume cases the small is fine with large being ok as well.

My next chambering is going to be a 6XC and its available in large and small primer pockets, I may get a small batch of SRP and see how long they last against the large that I'll primarily buy to see just how much longer they last if at all.

 

[PracticalTactical]

I'd be interested to hear how you make out with that.

 

[ShtrRdy]

I think there is also the belief that since the common benchrest cartridge, (6mm PPC), uses a small primer that it is needed for the best accuracy.

When you were having troubles with small primer in 6.5x47L did you try the CCI Magnum primer?

 

[antithesis]

I have a 308 that does not care one way or another. My 6.5CM's don't like SRP in close to or below freezing. I cannot say that I have noticed any benefit in pocket lifetime or accuracy, but I do seem to have an easier time finding loads that I like using SRP's.

 

[Milo 2.5]

I’m curious what your opinion is on these small primer cases vs the traditional large primer versions.

Take for example the 308 cases from Lapua with a small primer… I get that because guys in FTR F Class or even a PRS shooter in Tactical division wants to run at higher pressures with better brass life. It's not for me, but they have no choice because it has to be a 308.

But what really sends me into a tailspin is rounds like the 6 Creed in small primer… or 6.5x47L or 6x47L… I just don’t see the benefit.

If a 6x47L guy wants more speed then he should just build a 6 Creed.

But why on earth would a 6 creed guy want a small primer… to what run even faster?

And all this at the risk of weak ignition, hang fires and wild velocity in cooler weather.

Now, I’m not throwing this out of my butt… 10 years ago I blew 300 rounds trying to develop a load for my 6x47L in January and got hang fires and velocity spreads that were all over the map. Eventually I started forming cases from 6XC brass to get the large primer and everything settled down to single digit ES… and all was well ever since.

Truth is, it seems to work for a lot of people. I myself felt the creed case was getting just a little big for a small rifle primer, and did manage a few hangfires with a 6 creed running Norma MRP and a CCI 450 magnum primer. The powder was too slow burning for the case fill.
I switched to RL 16 and a 205M and never looked back.
Did you ever try figure out why your 6x47 was getting hangfires in January, other than just abandoning the project. I'd lay money down you were running a fast powder and had terrible case fill< so please expound on it.
You sound like a guy who likes to point a finger w/o figuring out the why. If you wanted to buy XC brass, why did you not run an XC reamer into your barrel and be done? The 2 cases virtually mimic one another, sans 1gr of powder x47 wise.

 

[PracticalTactical]

When you were having troubles with small primer in 6.5x47L did you try the CCI Magnum primer?

It was a 6x47L and yes I tried magnum primers,,, several kinds.

Even if I found a load that was 40 ES one day... I would test the same load another day and get a 60 FPS ES in an entirely different velocity range.

Keep in mind that I weigh loads on a Vibra HT 220 g balance which is one of the best you will find, so it isn't that.

I weight sort my brass. I'd find 5 Lapua cases that all weighed as close as possible... and I chronographed everything.

I tried jamming, jumping in 0.003" increments... fire formed cases... neck turned brass with 0.004" clearance in the necks.

The moral of the story is that it was problematic at best no matter what I did with small primers, but it was wonderful once I started forming brass from large primer 6XC brass, but I also used 22-250 cases or 243 cases... and they all worked very well... except for the small primer lapuas.

Dan Dowling was the gunsmith with a Gary Schnieder polygonal barrel and once I started running large primer brass and eliminated the inconsistent ignition problems, the rifle would shoot 1/8 MOA groups at 100 yards.... no BS. It was awesome.

 

[PracticalTactical]

You sound like a guy who likes to point a finger w/o figuring out the why. If you wanted to buy XC brass, why did you not run an XC reamer into your barrel and be done? The 2 cases virtually mimic one another, sans 1gr of powder x47 wise.

Oh that is not the case at all bud.

I spent a bunch of dough on a custom rifle and shot 300 rounds desperately trying everything and anything.

I spoke with Herman Salazar about it at Camp Perry and nobody had a good solution other than use a large primer.

It was a pain in the butt and the last thing I wanted to do after buying 500 6.5x47 Lapua cases for it... and neck turning all of them.

But after what I went through, today I have every right to point a finger or two.

I did not re-chamber for 6XC.. I ran 6XC brass through my 6x47L resizing die, and fired it in my 6x47L rifle. 6XC was the closest in size and the easiest to re-form.

 

[TheOfficeT-Rex]

Truth is, it seems to work for a lot of people. I myself felt the creed case was getting just a little big for a small rifle primer, and did manage a few hangfires with a 6 creed running Norma MRP and a CCI 450 magnum primer. The powder was too slow burning for the case fill.
I switched to RL 16 and a 205M and never looked back.
Did you ever try figure out why your 6x47 was getting hangfires in January, other than just abandoning the project. I'd lay money down you were running a fast powder and had terrible case fill< so please expound on it.

I spent a bunch of dough on a custom rifle and shot 300 rounds desperately trying everything and anything.

I think you missed the point of his post - which was powder burn speed and case fill related.

I run large primers, but I'm prone to shooting when it's really cold outside, and no one seems to complain about ignition issues with large primers. If I was just chasing speed for matches, small primers have been shown by some to be more tolerant of higher pressures.

Is there much of a difference, probably not, but people have the option if they think their gun or game is better suited to one or the other.

 

[PracticalTactical]

ok if small primers are more tolerant of higher pressures, why would a guy run an X47 with small primers at high pressures when he could just run a 6XC or 6 Creed without high pressures?

And not get anywhere near an ignition problem.

And get even better brass life.

 

[Milo 2.5]

I think you missed the point of his post - which was powder burn speed and case fill related.

I run large primers, but I'm prone to shooting when it's really cold outside, and no one seems to complain about ignition issues with large primers. If I was just chasing speed for matches, small primers have been shown by some to be more tolerant of higher pressures.

Is there much of a difference, probably not, but people have the option if they think their gun or game is better suited to one or the other.

I caught all of his post, but after his lengthy explanation I agree with him.
I merely stated the small primer seems to fine for a whole lot of shooters and seems to be the craze today. And yes, one should understand almost every aspect of what will happen once the firing pin strikes a primer, getting a solid understanding of it could mean the diff between success and disappointment.
If I was to go back to the creed case, which is highly unlikely, my choice would be the small primer with the advent of a couple new powders, mainly RL 16. Excellent case fill and performance, with a slight downside of hard carbon which I can handle.

 

[Milo 2.5]

ok if small primers are more tolerant of higher pressures, why would a guy run an X47 with small primers at high pressures when he could just run a 6XC or 6 Creed without high pressures?

And not get anywhere near an ignition problem.

And get even better brass life.

Small primers aren't themselves more tolerant of anything, more material in the case head so pockets may last longer.

 

[Fig]

Maybe they want to run a heavier pill...

You’re the first person I’ve ever heard had trouble tuning ammo to a x47, which is one of the most forgiving cartridges I’ve ever shot. Crazy low SD/ES even using a powder throw. You must have been doing something seriously wrong if you shot 300 and did not find the perfect load.

 

[TheOfficeT-Rex]

ok if small primers are more tolerant of higher pressures, why would a guy run an X47 with small primers at high pressures when he could just run a 6XC or 6 Creed without high pressures?

And not get anywhere near an ignition problem.

And get even better brass life.

I imagine there's a million reasons, for not just buying a new rifle, such as already owning the rifle, or concern for barrel life, or not wanting to fire form, etc, etc. If we start talking calibre swaps, it kinda negates the argument between why choose one primer size over another in a specific calibre, no?

I caught all of his post, but after his lengthy explanation I agree with him.

I meant he missed your point, but I can see how I was less than perfectly clear. My B.

 

[Milo 2.5]

ok if small primers are more tolerant of higher pressures, why would a guy run an X47 with small primers at high pressures when he could just run a 6XC or 6 Creed without high pressures?

And not get anywhere near an ignition problem.

And get even better brass life.

I am not saying you are right or wrong, but thousands of guys contradict your theories daily,, esp with the X47 case. Hell I've shot 30K in 6mm and 6.5 and not once had your issues.

 

[Supersubes]

ok if small primers are more tolerant of higher pressures, why would a guy run an X47 with small primers at high pressures when he could just run a 6XC or 6 Creed without high pressures?

And not get anywhere near an ignition problem.

And get even better brass life.

Who says people are doing this? The 47 is a nice case, so is the XC and the creed. A 100 FPS window will cover all three of them. It’s all splitting hairs, and personal preference will always plate heavy in the decision. The small primer case heads are super tough, and I think there’s lots of data to prove that.

It gets into the teens during the winter here, and I’ve never had an issue with small primer anything(mostly the creeds, but the 47’s too). I routinely run standard large rifle primers in large magnums as well, no issues.

 

[PracticalTactical]

What I'm struggling with is how I had nothing but problems, but I chronographed all my load development and compared the data between loads and from one day to the next...

This has me wondering how you guys know that you haven't had any problems.

Are you actually chronographing, or just shooting plates and if you hit it, everything must be fine.

Keep in mind that I was working up the rifle for F Class with a 1/2 MOA bull to 1000 yards and needed a tight velocity spread.... so 40 FPS ES was not acceptable.

Now I don't want to offend, but how did you guys know if there was a problem or not?

Case in point... I have a buddy who contacted me yesterday because he's getting 80 FPS spread with Hornady Match ammo. He didn't know it was that bad until he actually chrongraped it.

 

[FUNCTIONAL]

Chronoing. Not every time I shoot it (not prone in matches) but every time I take a range day its chronoed. Stays consistent. Only seeing a 14fps ES with my 6.5x47 with small primers. Temps down into the teens all the way up to 100deg.

Curious what bullet you are trying this with? I've had issues with a creedmoor where changing the bullet was the magic trick, everything else being the same.

 

[Milo 2.5]

What I'm struggling with is how I had nothing but problems, but I chronographed all my load development and compared the data between loads and from one day to the next...

This has me wondering how you guys know that you haven't had any problems.

Are you actually chronographing, or just shooting plates and if you hit it, everything must be fine.

Keep in mind that I was working up the rifle for F Class with a 1/2 MOA bull to 1000 yards and needed a tight velocity spread.... so 40 FPS ES was not acceptable.

Now I don't want to offend, but how did you guys know if there was a problem or not?

Case in point... I have a buddy who contacted me yesterday because he's getting 80 FPS spread with Hornady Match ammo. He didn't know it was that bad until he actually chrongraped it.

What chronograph were you using 10 yrs ago when all these issues surfaced?
About the same time, I had my first 7 saum chambered, with my shooting chrony, my ES was 70 most of the time but that rifle shot some groups at distance that were unreal, 1450, 1650, and 1850 yards.

 

[47guy]

What I'm struggling with is how I had nothing but problems, but I chronographed all my load development and compared the data between loads and from one day to the next...

This has me wondering how you guys know that you haven't had any problems.

Are you actually chronographing, or just shooting plates and if you hit it, everything must be fine.

Keep in mind that I was working up the rifle for F Class with a 1/2 MOA bull to 1000 yards and needed a tight velocity spread.... so 40 FPS ES was not acceptable.

Now I don't want to offend, but how did you guys know if there was a problem or not?

Case in point... I have a buddy who contacted me yesterday because he's getting 80 FPS spread with Hornady Match ammo. He didn't know it was that bad until he actually chrongraped it.

i shot 3 6.5x47 barrels...i run a magneto speed on most of my prone matches where 60 rounds is the norm....the 6.5x47 with 123g lapuas..130g hybrids and 140g hybrids produced the lowest ESs-SDs of ANY caliber ive ever shot with several 5-6 shot groups in the 0-1FPS and i never had a 60 round reading over 21fps except when i had doughnuts.

ive shot a 260..260AI..6.5x47..300wm..6 creed..straight 6BR and a BRX and if i can get those little 6s to run 20 to 25fps im real happy.
i will also say that if ppl took larger chrony samples they would find that their 0-5-10FPS ESs would not hold true....EVERY barrel ive ever shot has ended up in the 20-30FPS range with a 50-60 round sample.

most of the brass ive shot is SRP...i shoot in anywhere from 15 to 105deg weather and have NEVER had an issue with SRPs...im not say it CANT happen...im just saying ive never had it happen to me or any of the guys i shoot with.

as far as high ESs and factory ammo(and ESs is general)i had a kid come out with a bergara 6.5creed...take it out of the box..zero it with 4 rounds and 2 shots later was banging a 10" plate at 850yds....25 rounds 5 at a time and he only missed 3-4 times...threw the magneto on and over 10 rounds he had a 60FPS ES...this was when i stopped worrying about and chasing these super low ESs.

 

[Hoyt7mm]

Alpha did a good write-up and alot of testing with SRP vs LRP

Switch Or Stay | Alpha Munitions

alphamunitions.com

I personally run SRP. Groups and SD/ES are more consistent for me. I've not had issues in cold temps here WI. Everybody's setup is different though.

My observation is that getting good ES/SD is more dependent on your reloading & brass prep technique.

That said, the x47 lapua case is just stupid good ES/SD wise, even when I am in a rush reloading. Talking ES of sub 20 at worst.

YMMV

 

[PracticalTactical]

Alpha did a good write-up and alot of testing with SRP vs LRP

Switch Or Stay | Alpha Munitions

alphamunitions.com

I personally run SRP. Groups and SD/ES are more consistent for me. I've not had issues in cold temps here WI. Everybody's setup is different though.

My observation is that getting good ES/SD is more dependent on your reloading & brass prep technique.

That said, the x47 lapua case is just stupid good ES/SD wise, even when I am in a rush reloading. Talking ES of sub 20 at worst.

YMMV

Well that was not the case for me with small primers, but was single digit with large.

With large primers I got the same speed so often that I had to turn off the chronograph between shots just to be sure it was actually reading the shot.

Bullets tested were primarily 115 DTACs but also Berger 115s and lapua 105s.

Shot the 6X47L rifle last weekend again with large primer cases and got 3 FPS ES at 2990 FPS using my Labradar… So obviously quite pleased with the case design... no argument there... just SRPs are cursed for me... and I since it shoots so well with LRPs, I have no reason to bother with SRPs.

 

[Supersubes]

Well that was not the case for me with small primers, but was single digit with large.

With large primers I got the same speed so often that I had to turn off the chronograph between shots just to be sure it was actually reading the shot.

Bullets tested were primarily 115 DTACs but also Berger 115s and lapua 105s.

Shot the rifle last weekend again with large primer cases and got 3 FPS ES at 2990 FPS using my Labradar.

Nobody is denying your LRP performance. Lots of us have been there too. Given the results of the article, and a room full of people stating basically the same experience, are you willing to concede that what you experienced was a combination specific anomaly?

 

[spife7980]

Still havent heard what powder was used

 

[Milo 2.5]

Still havent heard what powder was used

He got it from Herman Salazar?

 

[Supersubes]

He got it from Herman Salazar?

German Salazar was a big proponent of using the lowest brisance primers he could find. IIRC, RWS large rifle primers were his go to because of that. Pretty much unobtanium at the time I read it. I remember later on he did a test between the Lapua Palma and standard Lapua 308 brass. He found no improvement in spreads with the Palma brass, but he didn’t not report failures either. Can’t recall if he commented on durability. None of that was aimed at you Milo, only quoted because of Salazar.

 

[Milo 2.5]

German Salazar was a big proponent of using the lowest brisance primers he could find. IIRC, RWS large rifle primers were his go to because of that. Pretty much unobtanium at the time I read it. I remember later on he did a test between the Lapua Palma and standard Lapua 308 brass. He found no improvement in spreads with the Palma brass, but he didn’t not report failures either. Can’t recall if he commented on durability. None of that was aimed at you Milo, only quoted because of Salazar.

All good, my inner asshole surfaced on that one. I am out. I am glad the op's system seems to work for him. He is probably the only one in the country that needs to do it, but has it nailed.

 

[OLD308]

DT speaks on the subject in the included pic. He further explains in other post and articles that the SRP is only for longer brass life in high pressure applications. Where you are pushing the ragged edge of safe pressures. Ignition issue using SRP in extreme temperatures is why he still advocates the LRP.

 

[PracticalTactical]

Still havent heard what powder was used

I'd have to go back to my records to verify and I'm at work right now.

For sure I used H4350 extensively and probably V V-550, off the top of my head I don't recall what else... but there were others.

I guess all I'm saying is that for me at least I found it a lot more trouble to find the magic SRP formula that worked according to my chronograph that was consistently better than the large primer performance. Well, I didn't find it actually... LRPs proved better for me.

My own conclusions are consistent with what Tubbs concluded as stated in the previous post.

I just hope you guys have done your own comparisons. It's easy to do if you haven't.

But beyond that is the justification for "needing" SRPs in a X47 or 6XC for high pressures when you could have just selected a 6 Creed LRP if you wanted higher velocities in the first place without the high pressures. I see no "need" to run such pressures in any of them.

 

[Greg Langelius *]

The load consists of the primer and the charge.

I once asked G. David Tubb what the difference was, since he was, well, G. David Tubb, and he had also gone deeply into the small primer rabbit hole. (PS that was around 2000) When I think in terms of scientific method and load development, his is the name that pops into my mind immediately.

He said that initially, he was getting better results; but that once he considered the first sentence above, he worked on large primer loads, and found that the primer size simply demanded a slightly different charge to achieve exactly the same thing, and he went back to doing his load development with the large primers.

I strongly suspect that the same proposition holds true for Magnum vs Standard primers too; unless you're running so much pressure that the cup can't handle it, and really, that's just too much pressure anyway...

So, IMHO, the question boils down to just how good is your load development process?

In fact, the argument about smaller primer pockets lasting longer just may be the first evidence I've seen yet that the primer size may actually make a tangible difference. May...

Here's a question. If smaller pockets get too big, should it be possible to ream them out to large primer pocket size? Downsides?

There comes a point when the issue has nothing to do with money; and may reach the point where some expenses aren't all that necessary.

Greg