6.5 CM, 147 ELD, Lapua brass, RL16, OCW test.

[Supersubes]

Normally I'd do this at 530 yds but had a free day and wanted to stay local. I've been having really good results with the 147's and h4350 in my Creedmoor. On a whim I decided to try some Reloder 16. I couldn't find any published data so I called Alliant. They didn't have 147 data, but for the 140/143 eld, they gave me 39.6-42-6. I forgot to ask what their velocities were.

Load
147 ELd @2.177 (.020 off the lands)
Virgin Lapua brass
Reloder 16 40-42 grains.
CCi 450
No sorting or prepping of any component, except for running the brass over a mandrel.


The gun
AIAW, 6.5 CM (standard firing pin)
23.5" Broughton 5c
NF 4-16 ATACR
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Shot at 109 yds, prone/bipod/rear bag. Data is on the target. Not sure what happened to the third shot for 41 gr, as it felt fine. Its so consistent everywhere else, it must have been me though, but whatever. No sight adjustments, they started high and I let them crawl up the page. Here's every round fired, from the cold bore (5 foulers) on. I also didn't clean out the several hundred rounds worth of 147/h4350 I've fired recently.
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Pretty sure theres more speed here, but I'll need to test that some more. This gun works really well in the high 26xx's, and brass should last forever. Hardly a hint of pressure anywhere, and no sticky bolt. I took some case head expansion measurements. The first three charge weights expanded .0008", 41.5 gr was .0009", and 42gr was .0011"
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[Beneviolence]

Those primers look quite cratered to me, even at 40gr. If your brass is stretching (especially on a first firing), I would take a look at the headspacing. Other things may be oversized firing pin hole or simply loading too hot. I'm getting 2775 ft/s (or 2900 without pressure but doesn't group as well) on 140's so 2675 doesn't seem unreasonable from a 24".

 

[Supersubes]

Its the shape of the AW pin. Its got a square-ish edge, which pierces the surface, and causes a riser. Cratering says more about pin profile and fit than it says about pressure. This particular gun does this with all loads, in every barrel I have bought or chambered for it, regardless of primer size. Headspace is set at .001 short of go, to match virgin lapua brass which is .002-.003 short of go.

 

[kirtar]

Those primers look quite cratered to me, even at 40gr. If your brass is stretching (especially on a first firing), I would take a look at the headspacing. Other things may be oversized firing pin hole or simply loading too hot. I'm getting 2775 ft/s (or 2900 without pressure but doesn't group as well) on 140's so 2675 doesn't seem unreasonable from a 24".

The velocity pretty consistent with what Hornady lists for factory loading (2695 out of 24") and some of the max loads on the reloading data for 147g ELD Match

 

[Beneviolence]

Agreed it doesn't seem like that's in the realm of high pressure loading; I was just saying that if the primer cratering is an issue, those could be some things to look into (seeing as you took pictures specifically of them). I wouldn't want primer flow like that but that's just me.

 

[Supersubes]

I'll be recreating this test with some distance, but it looks like I'll probably end up where my h4350 node was. This bullet in the high 26xx's works fantastic.


This gun has a really shitty pin profile. The big radius means that when the protrusion depth is properly set, the parallel sides of the pin pierce the surface of the primer(like a sheet metal punch). Hard to measure the depth but the indention has matching parallel sides, which creates a bit of an illusion. Most of what you're seeing is actually down under the surface. There is a raised portion as well, but its pretty slight.
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Heres what most pins look like. This is an AXMC.
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I took another pic of the test brass. I haven't pierced a primer in forever, and when they're close, its pretty obvious, as the entire indention stands up above the surface of the primer.
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Looking back at the expansion figures from my initial testing of lapua brass using h4350 earlier this year, the two seem to be making near identical pressure when they're at the same velocity.