Sako A7 6.5 Creedmoor

[JimTom]

You’re considering a Creedmoor Bill?

[SCJ429]

SCJ429 I said I found a few tests not that I tested I own a grendel and swede which get shot the most at the moment but I have no doubt Ill get a CM when the right rifle pops up.

And its an interesting topic for me as plenty of the Deer hunting season down here usually corresponds with the first big frost ( -2 to 0 degs) and when at 1000m plus ammo can get exposed to -5 to -8 deg overnite.

A few references have mentioned that with CM SR loads another 0.5 to 1.0 gr was required to get similar speeds to LR loads, is this the norm ?

You would have to do the testing to see what combination gave you the best speed without pressure signs, obviously magnum primers will give you a little more energy than the standard primer. Does a standard LR primer give you more than a SR magnum primer? If you are looking for more speed then a little extra powder is a small price to pay.

If you are worried about ignition and in minus 30 degree conditions you can put the rounds into your pocket to keep them nice and warm.

If it wasn't for Lapua the Creedmoor case was dead in the water as no one would compete using the horrible Hornady brass.

[Flyer]

By Lane Pearce, Shooting Times: https://www.shootingtimes.com/editorial ... rass/99417

Altogether, I tested 16 batches of test loads and discerned a definite "better" performance bias with most of the Small Rifle primers. With a couple of exceptions, there was very little difference in average velocities, but the small primers almost always delivered reduced standard deviations and improved accuracy. I consulted Dave Emary, Hornady's chief ballistician and originator of the 6.5 Creedmoor, to share the good news.

He promptly poured cold water on my results.

According to Emary, "Typical 6.5 Creedmoor powder charges are simply too large to reliably ignite with Small Rifle primers under all conditions. They're just fine for .223 and similar capacity rounds; however, we're talking about nearly twice as much propellant. A Large Rifle primer is definitely needed to assure reliable and consistent ignition. If the throat is eroded and a round hang-fires, the bullet will plug the bore, and the reigniting propellant will likely fully burn before the bullet can began moving again. Skyrocketing pressures may damage the rifle and possibly injure the shooter."

I told him I appreciated his insight and that I'd get a second opinion.

Gotta love that last line

Now Bill, you should have at least provided the entire quote in context

If the "6.5 Guys" (https://www.65guys.com/) are getting 22+ loads from a single Lapua case at reasonably high velocities ("hot load" in their own words), then I would suggest the biggest advantage to using small rifle primers is brass life.

I've read 6.5 Creedmoor shooters complaining about case life with Hornady brass – specifically loose primer pockets after 5-6 refirings. Perhaps that explains why Hornady is so defensive

Personally, I'm happy to use srp brass at moderate velocities for several reasons:

We live in Australia – it never gets below 0 where I live.

Lapua brass is good . . . and expensive. The more life I get out if it, the better.

Starline srp brass is almost identical to Lappy brass, so provides a cheaper alternative for hunting. I have 200 Lappy cases and 50 Starline cases for this reason, I don't care if I lose Starline brass in the bush – it's cheap. The biggest difference is in the finish: Lappy flash holes are drilled, Starline flashholes need deburring; Starline mouths are usually rough and need trimming. Lappy brass is good to load out of the box (though I always FL resize for consistency). The only other difference is in the flash-hole size: 1.5mm for Lappy, 2mm for Starline.

I love my A7 Creedmoor and have no intention of shooting the barrel out of it. I've got a mild 123gr load for targets and a medium 143gr load for everything else. If I was an F Class shooter, maybe I'd push the boundaries with pressures and velocities. In which case I'd naturally be using srp brass.

FWIW, I use BR4 primers.

[Flyer]

A few references have mentioned that with CM SR loads another 0.5 to 1.0 gr was required to get similar speeds to LR loads, is this the norm ?

While I'm getting close to published figures with mine (BR4 primers), the difference in velocities between srp and lrp ranges from negligible to favouring one or the other depending on powder and primer brand. See both charts below:






Incidentally, this is from the same article as above: https://www.rifleshootermag.com/editori ... ate/329988

When temperatures plummet, propellants become increasingly difficult to ignite evenly, particularly those made of a double-base compound containing nitroglycerine. There goes the added consistency you gained by using a Small Rifle primer. Stubborn ignition could theoretically go so far as to cause a slight hangfire in extreme cold.

It’s worth noting that one of my favorite 6.5 Creedmoor propellants, Hodgdon 4350 (ADI 2209), is single-based, while another, Alliant Reloder 17, is double-based. A quick call to the manufacturer will help determine whether your favorite propellant flavor is single- or double-based.

[Flyer]

And lastly, this test saw srp beat lrp in group size and velocity, but lrp beat srp in SD - make of it what you will!

https://rifleshooter.com/2018/05/does-p ... mparisons/

[JimTom]

As usual, very informative and well written posts. Thanks for posting Flyer.

[Bill]

You’re considering a Creedmoor Bill?

not right now JimTom but I do see a Short action with an IBI carbon wrapped 6.5 barrel, lightweight Carbon/kevlar composite stock in the future. 6.5 CM, 260 rem

[JimTom]

Sounds good mate, let us know when you get it.

Ummmm you do realise that if you end up with a 6.5 Creedmoor you may have to stop paying out on the cartridge?
No more 6.5 ManBun / Britney etc

Next I just need you to try a 300AAC and see how good that is and then you won’t be able to bag it out about being a transgender round either mate.

Just kidding mate.

[Bill]

hey the 6.5 CM is still the new kid on the block and its still may get dumped in favour for a more efficient flatter 6mm

I havent had 6mm for 23 years and the Creedmoor may have peaked, it will be a fallow/range build for 400m work.

[JimTom]

Yes I have read a bit online where people are favouring the 6mm over the 6.5mm. Creedmoor been around over ten years now I think, nothing compared to the Swede, however only time will tell if it withstands the test of time.

[bigrich]

They are talking about shooting in subzero temperatures. If Hornady made factory ammo and someone tries shooting it at minus 30, they want it to ignite reliably. I have used Palmer brass for my 243 and never had an issue with BR4 or 450 magnum primers. I never shoot in extremely cold conditions.

scanning through the topics, i came across this discussion you guys were having about small versus large primers. why does lapua make a small primer case in the first place ? i'm gunna be playing with 358 win in the near future, and using small primer lap cases is reported to give a gain of 100-150 fps gain in speed . that might not seem like the trouble for a lot of calibers but in the 358 win that pushes it's performance up into whelen territory . have any of you guys experimented with the different cases and observed any gains in ballistic performance

[SCJ429]

Cases like the 6mm PPC and the 6mm BR Norma utilise a small rifle primer and smaller flash hole which appears to aid their accuracy. These two cases dominate the accuracy world. This design feature has been added to other cases to see if a improvement can be made. Some people see an advantage in having this feature in their brass.

Using small rifle primers to provide you with more speed is only for those trying to chase it. It will not magically appear in your 358 by switching to Palma brass.

[Flyer]

You're only going to get more speed out of a small primer if you load it with more powder. Sounds obvious, I know, but the two advantages of the smaller primer and flash hole are stronger case (more metal around the primer pocket/case head) – which can equal higher pressures and longer brass life – and more consistent burn (less SD). At least that is the theory, and why srp 308 Palma brass came in to existence.

I load my rifle to normal pressures, as I'm not chasing speed. I use srp brass because it's been shown to last longer and I'm getting very good accuracy with it.

On a related note, I also shoot 223, so it means I can use the same primers for both my centrefires. The rest of my rifles are rimfires. 223 + 6.5 covers just about anything you could hope to shoot in Australia.

[JimTom]

Flyer are you using standard small rifle primers in your Creedmoor? I am guessing so considering you load both the 6.5 and .223 with the same primer. I am using small rifle magnum primers. I would be interested to see if there was any difference in performance, powder ignition etc.

[Flyer]

I use BR4 primers mate. I haven't been able to verify this, but I've been told by a local gunsmith (who's also a national benchrest champion) that BR4 and 450 primers are the same. The only difference is they are batch tested and the most consistent batches are labelled BR4 and the rest are 450. They both have 0.025" thick cups compared to 0.020" for the 400 primers.

I did find this page which lists some very slight differences, but I think 0.0005" difference is within margin-of-error/tolerance, so there's still a good chance they're the same primer: http://www.jamescalhoon.com/primers_and_pressure.php

I was lucky to pick up 1000 BR4s real cheap a couple of years ago, but since I load them for two rifles, I went through those pretty quick and am back to paying exorbitant prices for primers again!

[Flyer]

This guy tested 450 vs BR4 and also reckons they're the same: https://forum.snipershide.com/threads/c ... e.6402744/

I should probably save some money and start buying 450s.

[JimTom]

Thank you mate, well for what it’s worth I have found the 450’s to be fine. In saying that I am not shooting competition, just hunting, however it does shoot quite well on paper too.

[sungazer]

@bigrich I dont think you will see any gain in velocity. When I was testing with the 308 using different size flash holes I found the small flash hole in Lapua 1.6mm gave me 20fps slower than a large flash hole of 1.8mm. However the smaller flash hole gave a better ES and SD and also grouped better.

[SCJ429]

I use BR4 primers mate. I haven't been able to verify this, but I've been told by a local gunsmith (who's also a national benchrest champion) that BR4 and 450 primers are the same. The only difference is they are batch tested and the most consistent batches are labelled BR4 and the rest are 450. They both have 0.025" thick cups compared to 0.020" for the 400 primers.

I did find this page which lists some very slight differences, but I think 0.0005" difference is within margin-of-error/tolerance, so there's still a good chance they're the same primer: http://www.jamescalhoon.com/primers_and_pressure.php
!

CCI say that you use the standard data with BR4 primers, which means the charges are the same between 400s and BR4 the difference is only the cup thickness.

https://www.cci-ammunition.com/products ... aspx?id=27

[Bill]

Bigrich a simple change from ADI to Alliant reloader powders adds 100-150fps for the 358win, 200 to 250gr

[Flyer]

CCI say that you use the standard data with BR4 primers, which means the charges are the same between 400s and BR4 the difference is only the cup thickness.

https://www.cci-ammunition.com/products ... aspx?id=27

Thanks for the link. Nothing better than going to the source foe accurate info

[SCJ429]

I swapped 450 for my BR4 in a 223 shooting 80 VLD and it shot with lower ES. I did the same with my 6BR and the ES went up no matter what I did. I am always learning something.