Thread: 6.5 Creedmoor load development

This stage of the development is were it got hairy and disappointing and I very nearly scrapped the cal all together.
From here on my once fired Lapua small primer brass was tumbled OAL trimmed, deburred, uniformed flash holes neck sized only and I bump the shoulders back just a couple of thou.

I ran numerous ladder tests with both the 130gr TMK and the Lapua 139gr Scenar that were the favoured bullets at initial testing, both of which showed great dimension and weight consistency but pressure signs were very early to raise their ugly heads in both 2208 and 2209 powders. The 2208 was expected due to its faster burning properties and max loads for that in my rifle were around the 38.2gr with the 139gr bullet.
The 2209 on the other hand was just disappointing in both early pressure signs and accuracy. Although slower burning than the 2208 it is a little bulkier which meant anything over 41gr had the projectile up against it and bordering on a compressed load.
Something I found out really early with this case even when I tested some slower powders is the adverse pressure gain as soon as the powder was at full case capacity or slightly compressed.
I also noted some aggressive primer cratering with the Federal match primers *(more than my rifles normal rolled crater cause by the loose firing pin hole) and slow ignition on the compressed loads (mild hangfires) so I tried some of the harder capped and hotter CCI primers. I tried the std CCI 400, the hotter CCI 450 SR magnum and the benchrest CCI BR-4 primers all of which reduced the cratoring back to normal levels and showed a lot less flattening around the edges. I had to give the CCI BR-4 the slightest edge over the others but only because it showed a slightly better velocity std deviation than the others although still not as good as the softer Federal gold medal match primers but the trade off for the risk of a punchered primer or hang fire to me was a no brainer.

This month long escapade took me down the road of looking for lighter bullets as I was starting to think the 140gr realm for this cal was optimistic at best and maybe should be left for .260Rem and larger cals.. I was in the mind set that creedmoor will be more suited to the 120gr range.
Even after testing some 123gr Lapua Scenars I have a stack of, (my Grendel's favourite diet) I was left feeling flat as unlike its 139gr big brother the group size with the lighter 123gr bullets opened up as the velocity increased in my rifle and my expectation of this cals long range ballistics faded. I already have a 6.5 Grendel capable of 1000yds with theses 123gr so why do I need a Creedmoor that does the same thing only a little flatter with all the extra powder inefficiencies and headaches it has brought me?



So rather disappointed with the lighter bullets and both the ADI powders I shelved them and went searching for something that may get me a little more velocity in the 130gr to 140gr pills with a shorter barrel but keep the pressure to a minimum.

After a lot of research I found the Sierra web site mentioning some respectively fast loads for the 130gr TMK and 142gr SMK which my rifle seemed to favour, the powder they were listing was Aliant RL16 and RL17. Both seemed to get good speeds but after researching a little deeper the RL16 had better temperature stability and was a little slower burning so should produce slightly lower pressures than the RL17 in the Creedmoor case.
It was ordered and I eagerly awaited its arrival.



While waiting for its arrival I also found the new match bullet, a 136gr Lapua Scenar L bullet which seemed like just what the doctor ordered, a super high BC comparable to the 139gr but shaped a little different in the boat tail and a sharper ogive angle like a Berger match bullet. Many match shooters will know this design can be a lot harder to tune a load for but can be more accurate than its counterpart once all things are equal.

Left to right: Lapua Scenar 123gr, Lapua Scenar 136gr L, Lapua Scenar 139gr



I tried many other bullets and other components along the way but none of them are worth a mention here, just a lot of trial and error like most load development. Ill try and keep just to the relevant info.

It was here that I had my first real win with this cal. The RL16 had arrived and I had worked up some much better velocities with the 139gr Scenars using ladder tests of 0.1gr increments again stopping at the first signs of pressure. The RL16 seems to be the ticket in this cal and I was reaching speeds of 2950fps with only minor pressure signs starting to show, nothing even comparable to the 2209 pushing the same bullet at 2730fps.
However I was noticing the same issue as the ADI powders where pressure spiked as the case got to full capacity and the projectile contacted the powder when seated.
This is where I started doubting the pressure signs I was seeing and started thinking maybe it was the small primer pocket masking a lot of what was actually happening.
To rule this out I picked up some once fired Federal large rifle primed brass and fire formed them to my chamber, they got the same match case prep treatment as the Lapua brass got as well as annealing.




I then loaded them with a Federal gold medal match large rifle primer, this is a primer I have used for about 15 years in many cals and was very familiar with it characteristics in .308win.
I dropped the same lighter charge of 42gr of the RL16 behind some 139gr pills in both the Lapua brass and the Federals and ran them over the chrono.



The Lapua brass shot an average of 2796fps and the Federal shot an average of 2875fps. Same Load, different brass.... 80ish FPS difference in speed between the two, now Im getting somewhere. real world pressure signs I could read with confidence.



(note: the very slight polished wipe mark close to the primer on the lapua brass was from an earlier firing before I polished of the sharp edges on my bolt face)

As you can see the Lapua case still shows no signs of high pressure, yes it has the rolled edge cratoring but as I have explained this is normal in my rifle and is no better with a super light load. Look closely at the edges of the primer and you can see it has barely flatted at all, it still has very rolled edges and there was no wiping or ejector marks which this rifle is prone to showing at the slightest pressure spike. The case grew within normal specs and there was no brass migration or gain in OAL.
In fact I can run this lapua brass as high as 44gr with the RL16 (2950fps ish) before I start to see faint ejector rings and flatter primers in my rifle.

Now let's look at the Federal brass in contrast. It scared me a little and in hindsight I should have worked up from a lighter load with it to start this test. The primer was flat and the crater had sharper edges too. There was a definite ejector ring and wipe on all the federal brass and the bolt had a noticeable drag on the lift. Unfortunately this picture doesnt show the wipe as bad as it was but it was the only pic I took of this test.
Moving on from the obvious signs I started measuring the dimensions of it.. heres where it got ugly.
The primer pockets were stretched to a point where the primers could be seated by a push by hand on a table top.
The case had grown in length, (I didnt document the actual measurement) This brass had the same treatment as the Lapua brass with a neck size only and a slight shoulder bump of a couple of thou so it was not due to excess head space or or over resizing the shoulder etc..
This was an "all cards on the table" very high pressure load brass migration was obvious and the swelling around the base of the cases cup was visible to the naked eye. The case had been pushed well beyond what its natural spring back allowed and pressures were far too high. Continuing on with this load in this brass would eventually result in case head separation and or primer rupture.

The Federal brass is at the front of this pic, Lapua behind it. Look at the dark section at the base of the federal and you can make out the bulge.




Now this part of the test although a little stupid on my behalf taught me something and changed my mindframe to what I now know and put me on a path to find better brass that can cope with what I feel is the Creedmoor's biggest design flaw.. spiking high pressures right as you reach respectable speeds and accurate velocity nodes.

Now I hear you all ask with baited breath "what brass is available that will trump Lapua's offering of the small rifle primer brass that has got me to the results I have so far???....

Originally Posted by Wingman

....The 2209 on the other hand was just disappointing in both early pressure signs and accuracy. Although slower burning than the 2208 it is a little bulkier which meant anything over 41gr had the projectile up against it and bordering on a compressed load......

Just goes to show how much variation there is between different rifles. With my Tikka T3x 6.5 CM 45gns of 2209 will only reach slightly below the neck shoulder junction with Lapua fire formed cases. My overall cartridge length with the 140gr ELD-M is 2.940 and the base to ogive is 2.240 - both measurements seated .010" off the lands. I don't use 45gn 2209 in my rifle but have done so safely.

The best thing I did after I bought my 6.5 Creedmoor was to ditch my old CHRONY as it was very inconsistent in it's accuracy and buy a Labradar. Currently testing the Peterson SR brass too.

Please keep up the excellent reports Wingman - very interesting.

Originally Posted by 10-Ring

Just goes to show how much variation there is between different rifles. With my Tikka T3x 6.5 CM 45gns of 2209 will only reach slightly below the neck shoulder junction with Lapua fire formed cases. My overall cartridge length with the 140gr ELD-M is 2.940 and the base to ogive is 2.240 - both measurements seated .010" off the lands. I don't use 45gn 2209 in my rifle but have done so safely.

The best thing I did after I bought my 6.5 Creedmoor was to ditch my old CHRONY as it was very inconsistent in it's accuracy and buy a Labradar. Currently testing the Peterson SR brass too.

Please keep up the excellent reports Wingman - very interesting.

Thank you for those OAL figures buddy, that goes to confirm my theory of various throat lengths from the various manufacturers.
I can now make sense of how you fit larger 2209 charges without the high pressures I was seeing in early testing.
My modified throat now take loads almost the same dimensions you have given me and Id have no doubt if I replicated your loads now they would be safe in this rifle "hypothetically speaking and considering all other variables such as barrel internal diameters twist rates and rifling design and drag were equal.."

When the Remington was set up in its std tupperware stock with the internal mag, the internal mag dimension was 1.80" give or take but there was no way you could seat your bullets out even that far in this rifle because even if you could get them to feed past the feed ramp they logged well into the lands at that length.
I think it would be fair to say even certain factory loads in this rifle would be running too much pressure. The Hornady super performance for one would be a brass killer should someone want it to feed to one of these std factory chambered Remingtons.