Reply With QuoteNo, they feel normal. My gun has cratered primers from day one in factory ammo or reloads, even very light reloads. It did it before I had the firing pin bushed and has continued with no difference after.Originally Posted by South Prairie jim
@Ernest T
Are you feeling any bolt lift resistance after these shots that display this primer cratering ?
No, they feel normal. My gun has cratered primers from day one in factory ammo or reloads, even very light reloads. It did it before I had the firing pin bushed and has continued with no difference after.
[QUOTE=Ernest T;512085]If you’re not feeling pressure then you’re not above the safe zone and if you’re not bumping shoulders more than necessary than personally I would live with primer dents and worry about more important things. I’ve never had a reason to bush any bolts or reduce pin protrusion to gain accuracy.
Looking at that primer shows no real pressure, and primer has no signs of flattening. It's looks
pretty typical around the strike edge. The only thing I'll dig on is the strike is not centered.
If too off centered, There could be uneven ignitions shot to shot.
Keeping my bad Karma intact since 1952
[QUOTE=South Prairie jim;512086]These are the cases from the 140 gr Hornady Black rounds, which were the first 20 rounds I shot through the gun last July. You can see, except for size, the firing pin strike looks a lot like what I'm getting today. I had the firing pin bushed because I pierced some primers with loads several levels below maximum.
On another note, I signed up to qualify for the 1000 and 1700 yard ranges at the RPR range in Burnet Thursday morning. I didn't get a good description of the process, just so and so will have you shoot some rounds at 1000 and 1700 yards. Nothing like qualifying at my home range which had a minimum qualification score.
Just curious. Is your home range that busy that they turn away folks that don't qualify?
[QUOTE=Ernest T;512094]They look fine to me, you don’t want light stikes or soft /weak FP springs..the target is the only thing that matters. Show that along side those primers.
These are the cases from the 140 gr Hornady Black rounds, which were the first 20 rounds I shot through the gun last July. You can see, except for size, the firing pin strike looks a lot like what I'm getting today. I had the firing pin bushed because I pierced some primers with loads several levels below maximum.
I’m not going to read 17 pages but if you’re creating Excessive headspace you’ll see primers that resemble those.
Good luck moving forward..
Ernest, here are both of our Bolt Head faces close up showing the FP protrusion. You said you measured this at .041”, but compare to the picture of mine, which I know is just under .035”. I’ve looked at & measured quite a few, and FP’s set around .040” or below look more like mine. I really don’t think it’s an optical illusion. And the fact your primers are still cratering like this, it must be more than what you are measuring. Have you thought of doing shims, instead of sanding down your pin? That’s what I would do. Or, if you aren’t able, & wanted to give me some dimensions, I’d be happy to make a few shims for you. Going all the way back to the first few pages… I really thought the protrusion was the main issue. And I still think it is.
And here is mine which I know is just under .035”! See how the Radius on mine is just above the surface? On yours the Radius is far above. Grab a couple Feeler gauges to equal .041” and compare to yours. Do you really think they match?
My home range is a private club, Temple Gun Club, as is this one I'm shooting at Thursday, Reveille Park Ranch. Both are worried about shooters keeping the shots on the property. You wouldn't believe the number of people who want to shoot from a distance that have no idea how to go about it. They show up at qualification without a ballistic calculator and have no idea how to determine hold overs. There's a road within rifle shot that runs behind the berm on the Temple Gun Club rifle range. The berm is a good 30' tall, but you could skip a short round over or fly one over with the wrong hold overs. They charge yearly fees.
I've been doing the calculations for a 1700 yard shot with my bullet/powder/rifle combination using the Hornady 4DOF app on my iPhone, a Kestrel 5700 with the Hornady 4DOF software installed, and the Shooters Calculator. The Hornady solution is going to be slightly different because Hornady apps use their own proprietary software for the bullets in their library and the Shooters Calculator uses the G7 ballistic coefficient to do the math.
The iPhone app says I need 78.2 MOA of elevation and 1.57 MOA of left windage with a 0 mph wind. The Kestrel is very close, it says 78.59 elevation and 1.57 left windage. That's almost 116 feet of elevation! I know the Kestrel has additional environment data categories that the iPhone app doesn't have, maybe that accounts for the difference. I ran the data in the Shooters Calculator as a bullet drop and it came out at 115'.
I have 63 MOA of elevation available with a 20 MOA rail on my rifle and don't have the time or inclination to change it out for a 30 MOA rail. I guess I'll be maxing out the scope and holding 15 MOA with the reticle. Its going to be an interesting morning. I wish I'd done a little practicing dialing some elevation and holding the rest while I was at the range on Monday, but I had no idea I'd need nearly 80 MOA of elevation for that 1700 yard shot given that it was only 34 MOA at 1100 yards.
No, they don't match, but my firing pin is almost square across the end -- it has hardly any radius. Thanks for the offer of the shims, I am concerned about taking too much off and having a gun that won't fire.Ernest, here are both of our Bolt Head faces close up showing the FP protrusion. You said you measured this at .041”, but compare to the picture of mine, which I know is just under .035”. I’ve looked at & measured quite a few, and FP’s set around .040” or below look more like mine. I really don’t think it’s an optical illusion. And the fact your primers are still cratering like this, it must be more than what you are measuring. Have you thought of doing shims, instead of sanding down your pin? That’s what I would do. Or, if you aren’t able, & wanted to give me some dimensions, I’d be happy to make a few shims for you. Going all the way back to the first few pages… I really thought the protrusion was the main issue. And I still think it is.
And here is mine which I know is just under .035”! See how the Radius on mine is just above the surface? On yours the Radius is far above. Grab a couple Feeler gauges to equal .041” and compare to yours. Do you really think they match?
I’ve actually been wanting to grab a new style Firing Pin to play around with anyway. I may just do that & make up some shims. Even so, the intermediate section of both older & new style firing pins should be the same. And the outside diameter of the shim would be slightly smaller than the OD of the Bolt Head shank. So I can make some with the new pin.
Oh, and concerning the Radius… while you don’t want it “pointy” in any fashion, (too much Radius.), you also don’t want too little.. or rather, a “flat” face. Honestly, the Radius on mine very much ideal Radius. It’s a nice Half Round face, but the Radius doesn’t extend past.
Yep, elevation increases a lot when you go out to the really long ranges. Shooting .50 cal at 2000m the arcs looked more like rainbows. At 1000m they looked like proper bullets. Fun having tracers :)
Well, that was disappointing. RPR is a huge, privately owned multi-use outdoor recreation area. The 1700 yard range is only open on Thursdays because they shoot over top of a large park area that's shared with their RV and tent camping area. There are some type of bicycle races this weekend so the 1700 yard range was closed today through the weekend. It's also going to be closed next Thursday for a three gun competition so the first time I can actually use it is on the 27th. I had no problem qualifying though so at least that's done, but I wish they had told me the range would be closed when I spoke with them on Monday.
These are the primers after shooting this morning, still cratering the primers.
After shooting today, I worked on the shape of the firing pin. I didn't shorten it any, just worked on the radius - you can see the end hasn't been touched so its still the same length as before .040-041. I think I'm done messing with it at this point.
I read earlier that you were bumping the shoulder .003 on a once fired case, is this correct ? Have you ever let the case grow until it resisted chambering before resizing ?
I'm down to bumping .001-.002. I'm getting a lot more consistent case length after resizing than I was earlier. Now I'm using a Redding full length sizing die and a single stage press instead of Lee dies and the turret press I started with. I have not let a case grow until it wouldn't let the bolt close.
If you haven’t found the beginning of resistance you’re only guessing on how much headspace you’re creating. As an excersize you could back the die off a couple thousanths, size and fire one case, then cycle that same case through the chamber, if no resistance back the die off another thousand, load and repeat until a fired case starts to resist chambering. Note that number from base to whatever datum you are using.
To what end Jim? I’ve followed the normal procedure, fire the round, then bump the shoulder. I’ve dropped the bump to .001-.002. The brass has been fired at least ten times and been bumped judiciously after every firing. How could it have too much headspace?
Is that what you think is causing the cratered primers?
I think it is certainly possible’ let’s say the once fired case is still .003 short and you create an additional .002 or .003
The end result is ensuring that you are not creating excessive headspace, you shouldn’t need to bump once fired cases or even twice fired, depending on how hot you’re loading it may take three times before you feel resistance to chambering s fired round. At least you could eliminate this from the search for the issue that’s causing this cratering. ( think of it as oversight review or just double checking)
i only mention it because you’ve posted on open forum, I’m not trying to troll or crash your program and if you don’t figure it out no one will know or care beyond casual conversation. We’re just trying to help if possible..
again best wishes moving forward
I don't think you're trolling, don't worry about that. I want to understand the logic behind your suggestion. I've learned a whole lot here the past 8 months and wouldn't dismiss anyone out of hand.
You're not creating excessive headspace by bumping the shoulder .001 to .002- just not happening.
You’re assuming you know the gentleman’s chamber dimension, and true it’s probably not excessive but in the long range/accuracy game we assume everything is broken until we fix it.
primer cratering doesn’t really show on paper but soft primer, short pin fall, weak firing pin springs, internal drag, stuff like that will definitely show on the chronograph as well as the target.
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