Bit of a backstory, I picked up a well-loved old HOWA 1500 chambered in 204. Not exactly sure how old it is, but we think it came from before HOWA switched to the Hogue stock (this one has an old Howa Walnut stock that has the two threads factory-epoxied into recesses in the timber as a stiffening mechanism). It has certainly done some work as a farm gun...
I didn't shoot the gun in its original 204 configuration, rather immediately shipped it to my gunsmith and rebarreled to 223 rem. The gun came back, so I procedeeded to load up some 62gr pills over a full case of AR2206H (25.5gr to be exact). That's essentially the max listed load for such a pill. I also loaded some 69gr SMKs over the
same charge, which turned out to be a bit of a crunchy, compressed load.
I took it to the range and shot some tight groups at 50m:
- 62gr TAP, 69gr SMK
- IMG_0117.jpg (419.74 KiB) Viewed 6608 times
Nevertheless, with the TAP loads I noticed where the firing pin struck, primers were bulging out like a little "tit":
- 62gr TAP, 25.5gr AR2206H
- IMG_0112.jpg (525.75 KiB) Viewed 6608 times
When I got to the fourth SMK round, alas I suffered a pierced primer (I am now very thankful of the HOWA vented bolt):
- 69gr SMK, 25.5gr AR2206H
- IMG_0115.jpg (374.43 KiB) Viewed 6608 times
- Pierced primer "deeper" than the rest
- IMG_0116.jpg (433.78 KiB) Viewed 6608 times
The thought then occured to me as a comparison, I should immediately compare against some factory ammo:
- SAKO gamehead factory
- IMG_0111.jpg (624.85 KiB) Viewed 6608 times
So that's what I did, and as you can see the factory SAKO ammo also exhibited the same, cratering primer problem, indiciating the factory is operating at a similar pressure to my handloads.
I understand this may be a problem with firing-pin hole slop, or perhaps a weak firing pin spring? So here's some pics of these parts out of the bolt:
- IMG_2531.jpg (530.42 KiB) Viewed 6608 times
- IMG_2532.jpg (470.46 KiB) Viewed 6608 times
- One side of the pin is still blued
- IMG_2538.jpg (198.32 KiB) Viewed 6608 times
- But the other side is a little "polished"
- IMG_2537.jpg (274.23 KiB) Viewed 6608 times
- Tiny bit of wiggle going in, but not hugely...
- IMG_2536.jpg (324.71 KiB) Viewed 6608 times
- IMG_2541.jpg (334.83 KiB) Viewed 6608 times
Can any of you wise folk tell what's going wrong here?
Cheers,
In2.