Donnington
Well-Known Member
Thank you mate. Look a bit deeper than mine so I’m buying into the firing pin theory. Also…can clearly see your OCD in the way you load every round with the stamp the ‘right way’ up!
Thank you mate. Look a bit deeper than mine so I’m buying into the firing pin theory. Also…can clearly see your OCD in the way you load every round with the stamp the ‘right way’ up!
Tell me about it , it never gives me a day off eitherThank you mate. Look a bit deeper than mine so I’m buying into the firing pin theory. Also…can clearly see your OCD in the way you load every round with the stamp the ‘right way’ up!
Very goodFixed that for you mate
View attachment 448620
Joking aside one can clearly see how the case has gripped the chamber wall at peak pressure as it should but there is some headspace that the unsupported head has blown out to.Fixed that for you mate
View attachment 448620
As an aside this post shows the importance of correct terminology.Joking aside one can clearly see how the case has gripped the chamber wall at peak pressure as it should but there is some headspace that the unsupported head has blown out to.
Thus, the firing pin indentation is not a fair representation of what it is doing before ignition.
The obvious headspace could also be robbing some firing pin stroke!
The headspace is not an issue, my 457 is the same, however, there could be room for an increase in firing pin stroke.
The older rounds had different powder that was very dependent on a crimp.Not related to the OPs problem really, but just speaking of HMR ammo issues in general. I've put hundreds through mine with no issue other than some split case necks after firing. Opened a new (old, but sealed) box the other day and within the first 10 rounds experienced a slow-burn and then a squib that stuck the bullet in the barrel.
I won't be using any more from that box, and I'll go through the rest of my supply. Any more from that batch is getting pulled apart and binned as well![]()

I stripped the bolt and gave it a good clean. Decided not to remove any material from the bolt stop as didn’t want to void the warranty.
Who the hell told you to remove material from the bolt stop? Idiot.I stripped the bolt and gave it a good clean. Decided not to remove any material from the bolt stop as didn’t want to void the warranty.
@One on top of two could you send me a pick of your bolt, in the ‘fired’ position so I can see the firing pin?
Here is mine - you can see it stops just flush of the bolt face. Wonder if yours protrudes a bit more?
The firing pin it out enough. You need to measure headspace next.I stripped the bolt and gave it a good clean. Decided not to remove any material from the bolt stop as didn’t want to void the warranty.
@One on top of two could you send me a pick of your bolt, in the ‘fired’ position so I can see the firing pin?
Here is mine - you can see it stops just flush of the bolt face. Wonder if yours protrudes a bit more?
With a rimfire you are at the mercy of the producer. If they sent the bolt out adjusted wrong.....I thought RF were a load and shoot rifle. It sounds more like CF land chasing and 0.01 grain counting. Mine didn't shoot due to ammo being rubbish do I sold it. Job sorted. Machining bolts and stuff whats it all about ?
The older rounds had different powder that was very dependent on a crimp.
If you inspect the old ammo with a magnifying glass you will see split necks, discard them. The rest will be fine.
See picture.View attachment 448656
Newer ammo has a different powder and seems to ignite easier so not reliant on a crimp.
This strike pattern is differentNot sure how useful it is, but here’s some example cases:
(Hornady, 17gr);
Your missing the context.Interesting that you think crimp (bullet neck tension) is not important, when F class shooters are so concerned about how much or how little neck tension affects accuracy and go to a lot of trouble to obtain consistent neck tension.
I'm confused, what is more common with CF rifles?@Smellydog I was trying to say its more common with CF owners due to the ability to fibe tune loads OAL etc you can with RF. All the same the HMR lost a big following in the UK since all the problems with squibs and damage to shooter's.