6.5 Creedmoor Lapua brass. Sm primer vs Lg primer
- Thread starter krw
- Start date
More availability along with more brand options for SRP's.
In terms of performance, SRPs can actually perform better than LRP's . . . depending on powder being used and in what temperature they're at when used in larger cartridges. They work great in my .308, but I don't shoot in temperatures below 40°F.
Small primer brass has more material in the base so the primer pockets hold up better if you are shooting hot loads.
I prefer SRP for all cartridges that I shoot often. Look into Alpha Munitions if you want some Lapua-quality brass that’s almost always available, and made here in the U.S. 
What firing pin size can you use on SRP brass? I am looking at an action that has 0.070” firing pin diameter w/ a 0.05” firing pin profusion. I notice most custom actions have a firing pin closer to .062, so not sure if .07 would be getting to LFP/LRP territory.
Don’t know much about how during pin protrusion affects it though?
Don’t know much about how during pin protrusion affects it though?
Back in 2019ish I purchased 500 6.5cm SR Lapua Cases. I received 400 SRP, and 100 LRP. I didn't make a stink about it at the time. Left the LRP's alone for almost 3 years. Finally got around to loading with them. If there is any deviation in my shooting, I can't tell. I think that the LRP's shoot the same as the SRP's. Just loaded the LRP's for a 3rd time about a month ago. It is nice to have more primer choices though with the SRP's...
New shooter here. About ready to start reloading 6.5C. I purchased 400rd of loaded Berger 140g Hybrid Target in LRP. The only primer size available currently in there loaded ammo is LRP. This was in hopes of using reusing the Lapua brass.
I'm almost at at the halfway mark of running out and starting to pick up components.
That being said, it seems going SRP from what I'm reading lends to better/more case head material if I were to push it and/or less hotdog in a hallway with the primer pockets in the long run. Also SRP availability vs LRP availability. Seems accuracy is reportedly the same.
So, since I'm only 400 in, should I start from scratch and dedicate it to SRP and sell off the LRP Lap brass? Or continue with the loaded Bergers with the LRP?
To all the veteran reloaders, I appreciate your insight! Thanks
I'm almost at at the halfway mark of running out and starting to pick up components.
That being said, it seems going SRP from what I'm reading lends to better/more case head material if I were to push it and/or less hotdog in a hallway with the primer pockets in the long run. Also SRP availability vs LRP availability. Seems accuracy is reportedly the same.
So, since I'm only 400 in, should I start from scratch and dedicate it to SRP and sell off the LRP Lap brass? Or continue with the loaded Bergers with the LRP?
To all the veteran reloaders, I appreciate your insight! Thanks
The only real downside about small primers is that you have to shoot a BR or Magnum primer as regular small rifle will have issues. Ive shot small primered Peterson 6 CM brass and its on its 5th firing with zero primer pocket issues with loads that are at or exceeding max charge.
As far as the loads go, I didn't see any difference in velocity when using BR2s/BR4s with the same powder charge. It's good to have options with primer availability.
I'd expect you could run into hangfire issues in cold weather.
I've shot down to -4F with Lapua SRP brass, BR-4 primers and H4350 powder without any issues.
You need a thicker cup than a normal small rifle primer has for pressure reasons. The BR and Mag primers have thicker cups.
I switched to alpha srp brass and used cci 450s with H4350. My first loads had single digit es/sd. Some of that may be brass quality, but using lapua lrp brass didn't yield nearly as good of results. None of the lrp brass was as good as the srp with the same gun, same barrel, power lot, temps, etc.
The group sizes are good with both lrp amd srp at short distances but I really noticed that beyond 600 yards with srp I had far more consistent hits.
Possibly it's just a more uniform ignition from the cci 450? That's really the only factor that changes between my loads; sizing, trimming, bullet, and neck tension are all the same(even considering neck wall thickness).
The group sizes are good with both lrp amd srp at short distances but I really noticed that beyond 600 yards with srp I had far more consistent hits.
Possibly it's just a more uniform ignition from the cci 450? That's really the only factor that changes between my loads; sizing, trimming, bullet, and neck tension are all the same(even considering neck wall thickness).
I prefer LR primers for both my 6.5 CM and 308 Win loads over the SR primer cases.
After using both for years, there are instances where the SR are inferior with certain powders, in shot to shot consistency, S/D, and accuracy can fall off.
Plus they lose 40 fps velocity over the LR primer with one powder with 230 gr 308 bullets when testing 10 shot groups, so you'd have to add more powder to get the same velocity with the SR primer.
The 308 hybrid case with a LR primer beat out both Lapua cases with SR being the worst in every category, S/D, accuracy, and low velocity with the same bullet and powdet charge.
So I don't load Lapua SR Primer cases these days, but have about 300 or so of each new in the boxes from years ago when I bought into the SR primer cases as being better, until I begin to use them with various powders and bullets, in a variety of conditions....then never purchased anymore, but ordered LR primed cases instead.
Want something that will handle your hotter hand loads get hybrid cases with LR primers.
After using both for years, there are instances where the SR are inferior with certain powders, in shot to shot consistency, S/D, and accuracy can fall off.
Plus they lose 40 fps velocity over the LR primer with one powder with 230 gr 308 bullets when testing 10 shot groups, so you'd have to add more powder to get the same velocity with the SR primer.
The 308 hybrid case with a LR primer beat out both Lapua cases with SR being the worst in every category, S/D, accuracy, and low velocity with the same bullet and powdet charge.
So I don't load Lapua SR Primer cases these days, but have about 300 or so of each new in the boxes from years ago when I bought into the SR primer cases as being better, until I begin to use them with various powders and bullets, in a variety of conditions....then never purchased anymore, but ordered LR primed cases instead.
Want something that will handle your hotter hand loads get hybrid cases with LR primers.
Stock a few of whatever you don't use for when primers are thin lol. Definitely enjoyed having both primer types in my 308 and 45 acp these last few boom lean years.
I even used shotgun primers in modified 308 cases for 175 gr subsonic rounds with sucess...so any primer available and still be able to shoot your firearm.
Why?
Because shotgun primers were always available in my area...when other primers were out...so lets see if they will work in an emergency with low pressure subsonic 308. The velocity was a little bit high but they were accurate for the intended use.
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I was speaking with one of the tech guys at Berger on the phone one day (don't remember if it was Bob or Phil, but it was one of those two). It was an unrelated matter, but he mentioned the change in their loaded 6.5CM ammo from SRP to LRP. So I said I had noticed that and asked why - because initially all of their 6.5CM loads came in SRP-only, but a few years later all I ever saw were LRP. His answer was, "Hunters." The reasoning behind using SRP initially was the fact (theory?) that it helps in lower ES/SD, as a result of the smaller flash hole creating a more concentrated jet of fire that penetrates deeper into the powder column and ignites it more consistently, whereas the larger flash hole of the LRP "blasts" the rear of the column and starts ignition more rear-to-front. (I have no idea if it works out that way, but this is their reasoning, and he mentioned .308 Palma brass as the model). The problem was that a lot of hunters were using their match ammo in much colder temps than typical matches are shot in, and were experiencing hang-fires/delayed ignition ("click-bang"). They got complaints (always from hunters in cold temps) and decided to just make everything LRP and it supposedly fixed the issue.
Take if for what it's worth, but the above came directly from their tech support guys.
I don't believe they will offer SRP in loaded-ammo again, but I believe you can still get the Lapua brass itself in SRP (I haven't looked in a while).
I thought magnum SRP is a requirement for reliable ignition in this case volume?
That's what I thought, just curious what's actually being used. If someone's having bad results it would be interesting to know what primer is being used.
I don't. Just standard SRPs. I only shoot in TN cold though, 20 degrees and higher, never in ND cold so that may be why I never have any issues.
Aside from the cup, doesn't the magnum primer produce a hotter flame front?
Id almost consider that more important than the cup thickness.
This is for everyone not aimed at your post only
I have shot quite a few 308Palma SRP loads as well as 6.5CM and 6.5x47 in sub zero temps and never had any ignition issues.
Pretty much all using CCI-450 and single base powders.
The CCI-400 work fine when used primarily with small firing pin bolts and tight tolerances or bolts that have been bushed.
I ran all of the 308win Palma brass in a non bushed Rem 700 varmint without issue.
I didn't run crazy pressures but on the top end of my loads definitely had cratering with the 450's but no surprise there.
Haven't tested it but with the mid size cases mentioned the SRP might have some issues with ignition of double base powders in cold temps.
I use Lapua 6.5CM SRP brass with standard primers in my Seekins HIT with H4350 and 6.5 StaBall. (though I did try mag primers to see if the StaBall would burn cleaner)
Strangely I have a Steyr that doesn't like the SRP / 6.5 StaBall combo, so I use Lapua LRP 6.5CM brass in that. (?)
(strange as well that I've mention this twice tonight on two different forums within a half hour or so)
I run 6 mm Dasher with 7 1/2 magnum primes.
The .025" thick magnum primer CCI 450, BR 4, or Rem 7 1/2 is for the high pressure or Win #41 for all AR type rifles with floating firing pins for safety, although I've never had a AR firing pin slam the thinner cups hard enough to detonate the chambered round, one can definitely see a small indentation where the firing pin slammed into the back of the primer when chambering.
Also use heavy cup SR Mag primers in 454 Casull, as recommended.
The .025" thick magnum primer CCI 450, BR 4, or Rem 7 1/2 is for the high pressure or Win #41 for all AR type rifles with floating firing pins for safety, although I've never had a AR firing pin slam the thinner cups hard enough to detonate the chambered round, one can definitely see a small indentation where the firing pin slammed into the back of the primer when chambering.
Also use heavy cup SR Mag primers in 454 Casull, as recommended.
I’m sure from a pure reliability standpoint you would be better suited to use magnums. I just had a bunch of BR4s so that’s what I use. If I ever have an issue I suppose I’ll blame the primer first. So far so good though.Aside from the cup, doesn't the magnum primer produce a hotter flame front?
Id almost consider that more important than the cup thickness.
This is for everyone not aimed at your post only
I'm curious how the standard primer effects performance, although that is tough unless we are considering one caliber, one powder, etc. There are so many variables to consider.
On mine, the performance of the 450 was so good when I first tried it I'd almost be silly not to keep the recipe the same.
I find a load at the velocity range I want and fine tune seating depth.
Then just run it until there is reason to go back and check velocity like a sizable difference in group size or drop.
No point in turning it into a long term science experiment.
I’ve got some H4350 I’ll load up with 140 ELDM’s and some Sierra 130 TGK’s and will post the results tomorrow. Have some Lapua brass ready to go and primed with BR4s. Needed an excuse to take the Garmin out anyways.
What distances are you shooting at?
No one is talking about long term science experiments.
100-1200 yards
First time shooting at 1200 with the load I initially developed with the 147eldm I estimated drop for my chrono velocity and advertised B.C..
Took one shot, was just off bottom edge of plate made adjustment with reticle hold and rang steel the next five shots.
Fair enough and more power to you.Unless that's why you're doing it. For some folks, that's the whole point.
I just like to shoot but experimenting is fun, I actually like reloading so maybe I'm a bit off anyways
Virgin Lapua SRP brass - 21st century 264 mandrel
22" barrel
BR4 Primer
ELDM 140 GR
40.0GR H4350
2.800 COAL
FPS - 2572
Spread - 19.7
SD - 7.5
BR4 Primer
ELDM 140 GR
40.5GR H4350
2.800 COAL
FPS - 2609
Spread - 38.7
SD - 14.1
Not terrible numbers, not great. I would hope to see them shrink now that they have been fired once.
22" barrel
BR4 Primer
ELDM 140 GR
40.0GR H4350
2.800 COAL
FPS - 2572
Spread - 19.7
SD - 7.5
BR4 Primer
ELDM 140 GR
40.5GR H4350
2.800 COAL
FPS - 2609
Spread - 38.7
SD - 14.1
Not terrible numbers, not great. I would hope to see them shrink now that they have been fired once.
BR4, GM205M, 7.5 are all Benchrest primers. CCI 450 is the only “magnum” SRP commonly available I’m aware of. To clarify my prior statement I should have said “benchrest or magnum primers” over say 6.5, 205, etc.
Are you talking using a small BR/Mag primer vs a small standard primer? A standard primer just doesnt have a thick enough cup to withstand the additional pressure in a 308 sized case. The difference in thickness is about 5 thou, 20 thou for a standard, 25 thou for a Mag/BR. That is a significant amount. BR and Mag primers generally throw a bigger spark as well. One thing of note? The CCI 41 is 25 thou thick, but I cant speak to if its behaves more like a standard or Mag primer as far as priming compound quantity.
Im not saying it will not work, because it might be just fine. But I have seen pics of a standard CCI 400 being used in a 6 CM where the primer was pierced and damaged the tip of the firing pin and the bolt face. Just not worth the risk.
