Primer Seating Depth & Accuracy?

[ridgeway]

Replace your firing pin spring...or see if anything in bolt/cock piece/shroud hanging up. Some cocking pieces are pinned and that pin can possibly drag. Fire control is big and guys write it off as it's not possible either because their action is new or I'm running brand x and it's not possible. Worth a check....

 

[MikeMcCasland]

Just put the barrel on a different action, different NF comp. Same lot of powder from a different jug, with hand seated primers.

Tried depths of N, N+.003, and N+.006 just to see if the depth node had jumped way out on me.

Nope. Barrel is done.

Screwing on a new Brux now.

Powder was N150. I tried to tune it yesterday with Varget from 43.6-44.8 and it was shooting horrible.

No carbon ring.

Best it did was 2in of vertical at 300. Sad.

 

[Dub]

thanks for the update Mike

 

[Dub]

what barrel was on it?

 

[MikeMcCasland]

what barrel was on it?

30 inch, 10 twist, 4 groove, HV Krieger.

Don't get me wrong, I'll buy more Kriegers. This thing shot amazingly well when I wasn't calling wind.

Just sucks cause I just had a bart die on me at 2k rounds last month, and now this.

Starting over with both rifles. New Bart on one that seems to like Varget, and now a new Brux on this one.

 

[urbanrifleman]

An 8 would be pretty bad. Primer seating is important but I think you would have to be doing some way out of the norm to get it that bad.

Firing pin?

 

[dryhumor]

I have Federal AR Match primers that have a noticeable difference in the compound quantity. I generally separate out what looks to be less, in favor of uniformity. The other week i just loaded up with no separating. I was essentially fire forming/load development. Pulled the trigger, click no boom. This on 20% or so of the rounds.

while I realize these primers are harder, out of curiosity I attempted to fire the once struck round. It would fire the second time round.

Could worth inspecting the amount of compound and its distribution in the primer.

 

[marchboom]

Primers are designed to be seated fully in the pocket. Not seating it completely could cause a misfire or a light firing pin strike that might not set off the primer with authority. The last thing I would want is for the firing pin the complete the seating of the primer, which is what happens when the primer is not seated fully when first installed.

Once the primer is fully seated how does one seat it any deeper without crushing it...even slightly?

I can see trying different brands of primers during the load development phase but trying different primer seating depths? Someone can positively see a difference?

 

[JimSC]

I can see trying different brands of primers during the load development phase but trying different primer seating depths? Someone can positively see a difference?

theoretically it could affect the lock time by a millisecond or something, not that in my shooting I would notice a difference

Shame on the barrel, had a 6 CM go from hero to zero suddenly at 900 rounds so I know the feeling

 

[Alex Wheeler]

Replace your firing pin spring...or see if anything in bolt/cock piece/shroud hanging up. Some cocking pieces are pinned and that pin can possibly drag. Fire control is big and guys write it off as it's not possible either because their action is new or I'm running brand x and it's not possible. Worth a check....

This is right. I go through every action I use. Last week I found one that was drag free out of the box. I cant remember if I have even had one I didnt work on that area, that could be a first. But, an 8 would tell me these fliers are over 10 inches out of the center of the group. Thats a pretty big "flier" I do not think seating the primers a little too hard is the problem.

 

[MikeMcCasland]

This is right. I go through every action I use. Last week I found one that was drag free out of the box. I cant remember if I have even had one I didnt work on that area, that could be a first. But, an 8 would tell me these fliers are over 10 inches out of the center of the group. Thats a pretty big "flier" I do not think seating the primers a little too hard is the problem.

Yep I found things I need to fix with the actions. I'm running Jewels on Pandas and I'm right at ~.225 pin-fall. I ordered two .030 hangers from Kelblys early last week, but they haven't arrived.


That said, when I can move barrels around and the poor shooting follows the barrel it's time to go.


The ammo I was using to troubleshoot the 'suspect' barrel shot pretty well in both the bart and the brux with minimal tweaks to depth.

 

[Uncle Ed]

Did you try switching to decaf coffee? Your biorhythms could be out of sync.

As you can see below you have to find the peak biorhythm node.

Sorry, the devil made me do it. I had the same problem with my Stevens 200 and Tasco scope.

 

[MikeMcCasland]

Did you try switching to decaf coffee? Your biorhythms could be out of sync.

As you can see below you have to find the peak biorhythm node.

Sorry, the devil made me do it. I had the same problem with my Stevens 200 and Tasco scope.

 

[RegionRat]

Sounds better that you are done with diagnosing and on the way to the next bbl...
Nothing worse than when guys waste too much time on a bbl that is done and go into denial...
Ask me how I know... LOL

 

[Mike F H]

Sounds better that you are done with diagnosing and on the way to the next bbl...
Nothing worse than when guys waste too much time on a bbl that is done and go into denial...
Ask me how I know... LOL

Have you tried another scope?

 

[RegionRat]

Have you tried another scope?

If I find myself in Mike's situation, the scope is high on the troubleshooting list, as is the stock and the firing pin, and ammo.

That is just because of my odometer and having lived long enough to have failed all of those things many times...

It takes several bbls in more than a few contexts to come to grips with giving up on a bbl, at least it did for me.

I was lucky to have far more experienced friends who moved me along through that learning curve or I am sure I would have spent even more rounds and trips in denial...

 

[cw308]

Mike
Hopefully the next time we hear from you it will be good news , would love to know what caused the problem , seems like something loosened but you covered all bases , barrels don't just drop off like that , you scoped the barrel , everything looks good no build up or washed out . Makes for a restless night for sure .

Chris

 

[orkan]

Gentlemen, A customer was kind enough to direct me to this post. I'll share a small piece of information, and then leave you back to your discussion. Comments or questions can be directed to me at 605-554-1911, as my participation here is quite limited.

Since the inception of the CPS, I have considered primer seating depth to be one of the most overlooked aspects of precision handloading. I have long preached its importance, but that effort is often met with skepticism and hostility. I wrestled with the decision to provide one thousandth of an inch clicks in the CPS, as I thought they were perhaps too coarse. That's how precisely I think it should be considered. Ultimately we went with one thousandths instead of five ten-thousandths... however, there is plenty of room for that in the design. Many customers run between clicks to get their desired adjustment, and do so with great success. Witness marks can be added to the elevator wheel and the top plate to achieve resolutions as small as 2 ten thousandths, though I feel the CPS would need some design elements added to truly achieve that resolution.

The CPS allows for primer seating depth testing to be conducted much in the same way that bullet seating depth testing is accomplished. Just as with bullet seating depth testing, primer depth testing is very much component combination dependent, right down to the lot number... just as other component testing would be. What I mean by that is, the right primer seating depth is specific to the batch of brass, primers, powder, and bullet, as well as the other normal sets of variables such as the rifle, conditions, etc during loading.

The definition of success regarding primer insertion should be looked at with much more scrutiny than simply whether or not it's placed securely in the hole. Stories like the OP's do not surprise me, but rather the lack of conversation regarding this topic surprises me. I think many shooters have had their success sabotaged by their priming process, without them knowing or considering it.

 

[MikeMcCasland]

Okran - Thanks for the post! Always good to see the mfg step into threads like these.

I want to be clear about this thread. The only reason I was even looking at primer depth was because it was the only procedural change that coincided with the down-turn in accuracy. I had some doubts about minute adjustments to primer depth playing a meaningful role in accuracy (and to an extent still continue to have those doubts).

That said, I'd searched quite a bit on the forums, and came across some posts from Bart and a few of the other 'heavy hitter' SR BR guys saying they'd run tests and could see a difference; unfortunately they didn't quantify how much the various primer crush variations impacted groups. As I listed in the OP, "groups expanding" means something very different to an SR BR shooter than it does to a LR F-Class shooter.

At the time of all of this, the barrel had 700-800 rounds through it when things 'gave out'; my assumption was a barrel acting flakey that early on is/was a near impossibility (especially considering how well this one shot).

Much to my dismay though, it does appear that the barrel is the culprit (points to Doug for calling it). I shot it the last two days leveraging every trick I know, across two actions/scopes/stocks, and it just shot poorly. When I screw a new Brux on there, things tightened up to what I'd expect from a good barrel that isn't in perfect tune.

Lastly, I will say the CPS is a very nice piece of gear. I like my reloading gear to be 'overbuilt/overkill' and that's kinda how I'd classify it.

 

[JimSC]

The CPS allows for primer seating depth testing to be conducted much in the same way that bullet seating depth testing is accomplished. Just as with bullet seating depth testing, primer depth testing is very much component combination dependent, right down to the lot number... just as other component testing would be. What I mean by that is, the right primer seating depth is specific to the batch of brass, primers, powder, and bullet, as well as the other normal sets of variables such as the rifle, conditions, etc during loading.

have you actually done any testing to show how much or any difference it makes? I would think if there were ignition problems due to primer seating depth it it be reflected in the velocity numbers