Light Primer Strikes/Reloading Question

[navybowhunter]

Question for some of the smarter reloaders on here.

Loaded up 500 Sierra 77 Grain (Moly) SMK's, in mostly new Lapua brass, some once-fired (*resized* and trimmed) for my visit to Ramseur a few weeks back for a KD shoot.

Primers were CCI BR4's, and 24.0 grains of BLC-2 powder.  COAL was 2.235", and trim to was 1.750".

MV on this load was very consistent, 5 shot group yielded me .817 MOA at 100 yards, AVG velocity was 2569 FPS and SD was 9.5.

I posted earlier about my trimming issues, IRT to sizing die setup.  Hopefully I have fixed that issue now with the Hornady LNL Headspace Comporator kit.  In fact I am sure from what I have read that issue will be dead next reload session.

Had a few issues, and although I could post in AR15.com, I like the "respect" that people tend to have for others in this forum.   

So here goes...., On the first few COF's, When I performed a magazine change (from 2 to , using the bolt release on the receiver, rifle would go "click", and no BANG.  Frustrated, I would rack the charging handle, and issue appeared to go away. 

In other words, magazine was seated properly (or at least I think it was), cause there was a round in the chamber.  Primer showed an ever so slight "indentation", but not enough for ignition.

What could this be indicative of?  Would the headspace issue discussed in my "trimming brass" question cause this?

I started to get frustrated and opted to use the charging handle to release the bolt, vice the bolt release on the receiver.  This seemed to help.

Could it be, that the 100 once fired brass, that is mixed in with the 400 new brass, was not chambering properly?  Barrel had less than 110 rounds thru it.

I managed to get my KD qual in spite of this issue, but did have a few stages where I did not get 10 rounds down on paper. 

Fired brass does not exhibit any signs of overpressure, primer strikes are normal, no bulges, no flattened primers, necks look as expected.

Rifle specs, cause maybe that is the cause?  Home built AR15, JP Enterprises Supermatch .223 Wylde 16" barrel 1:8R, JP Headspaced supermatch bolt (to my barrel), Adams Arms BCG and piston kit, Heavy Buffers anti tilt buffer, seemingly weighted properly, as it is stripping rounds properly from magazine, and bolt does lock home on last shot.  MAGPUL UBR stock and magazines.

Looking to get to the bottom of this.  Appreciate any help.

Respectfully,

Chris

[navybowhunter]

Some amplifying info:

Buffer, on this build I opted for a Heavy Buffers Inc, Anti Tilt Buffer system.  Hear a LOT of good things about it, but...., it is a pain to separate the upper from the lower, due to this system.  Not a big deal but what, there is more....

When I built the rifle, went to the range, could not get the bolt to "lock back" on the final shot.  NOR could I get the bolt to lock OPEN using the "bolt catch" on the lower.

This particular buffer uses "weights", to tune the system.  Changed to a lighter weight, still no joy on bolt lock back.  Finally, thinking that the buffer was possibly a bit "too long", I sanded 1/1000th or so off the polyurethane buffer.  Whalla, it locks back, albeit with significant force on the charging handle.

Could this buffer be causing an issue?

At a loss, and I am a perfectionist, looking to correct the issue.

R/
Chris

[Big John]

Ok, others who are better will comment more, but here's a few things.

1. The light primer dents are from the free floating firing pin of the AR. You are not seeing
a light hit. To check, run a mag through the rifle, and manually eject one mid mag, it will have this.
Also, any of yours you cycle manually will have that dent. Of course, if you fire it, the dent gets
replaced. Do not single load one and let the bolt slam home, that may slam fire it. Feel free to single
load one and ease bolt forward and fire it that way.

2. You need more data. Try new brass, or commercial ammo, firing from mag change, some with bolt
release, some with rack and let fly. Also try same with resized. Isolate problem. Also, INSPECT bolt
to make sure fully closed. I think you are having a chambering issue. Try commercial ammo for a while
to eliminate your reloads as bad.

3. Magic marker a once resized reload, a new reload, and a commercial round, and check and see what
the chamber scratches off. You may have a tight chamber.

[Guntuckian]

Do you disassemble bolt down to firing pin and clean both firing pin and firing pin channel?  Do you have any carbon build-up?  Does your trigger reset properly when dry firing and manually operating the bolt?

Light marks on primer are normal due to free floating firing pin. But, you say you hear a click.  Is it a reset click or a firing pin release click?  You can determine this by dry firing, holding trigger back, manually operating bolt, then releasing trigger and listening.

Don't have any live ammo in room when verifying trigger reset sound!

--gb

[eagle223usa]

It sounds like you may be setting the shoulder back a bit too much.  If letting the bolt fly forward from the bolt release is causing this FTF situation it could be that the round is slipping forward too far into the chamber, as in the shoulder is set back a little far.  Check the primer on a fired round, (one that did go off) is it protruding just a bit?  Try setting a few on a flat surface and see if they wobble or just fall over.  This is a sure sign that the shoulder is set back just a bit too much during sizing.  If this is the case get yourself a case gauge, mine is made by Wilson.  Its a great tool for setting up a re-sizing die.  Hope this helps. 

[jmdavis]

I'm thinking the buffer, if I had another, I would try it. While I will run the Chrome Silicon springs from David Tubb, I always go with the standard Spring.

Secondly, how does the rifle act with normal 55 or 62gr ammo?

[eagle223usa]

Oh, and with the buffer, Check the top buttstock screw, the one that goes into the rear of the buffer tube, I have found a few (A2's) that were a bit too long and hit the rear of the buffer at full recoil compression. Hope this helps.

[Agrivere]

A question. If I'm understanding what you're saying, you would load a 2 round mag for the rapids, fire two shots, and change mags. Since you were hitting the bolt release on the 8 round mag, the bolt was locking back on the now empty 2 round mag, correct? You would then pull the trigger and get a click but no bang. Pulling back the charging handle and rechambering a round seemed to fix the problem? The big question is when you did this, did an unfired round eject? It sounds like it did not.

My suspicion lies with your buffer weight system. The fact that it wouldn't hold back the bolt until you shaved it is a clue. I think the heavy buffer system isn't allowing the bolt to always go back far enough to chamber the next round after a mag change. Pulling the charging handle fixed it because the bolt goes back a little further when you do that.

Heavy buffers and bolt carrier weights have their fans, and I hear good things from those who like them, but they are certainly not necessary. Plenty of match grade ar15's will shoot sub MOA without them. I haven't used one but I would question whether the hassle of disassembly and the possible reduction in reliability is worth the small improvement in lock time.

In answer to your other question, yes it's possible for the headspace issue you mentioned earlier to cause a round not to fire, but it would have to be a LOT of excessive headspace and it wouldn't have anything to do with freshly loaded mags. I don't think that your problem is there.

[Yooper75]

Check your gas tube alignment because I had a similar problem with my AR-15 the gas tube wasn installed at a slight angle causing the bolt to rub on the gas tube just enough to hang the bolt causing a light strike. Also try pushing the bolt forward with using either the forward assist or your trigger finger and make sure your rifle is lubed well with no carbon build up in the bolt carrier. You may also want to try switching primers to see if that makes a difference or try your ammo in a different rifle to see if you get the same result.

[navybowhunter]

Updated below

[navybowhunter]

Updated and Edited:

Got home and really took my time getting measurements.  I took the time to "zero" the caliper with the Hornady comparator installed this time.  I also noticed that any "hi" primers will give an erroneous reading.  Reseated any "Hi" primers in the press.   Speaking only of loaded ammo, on the Hi Primers.

All of my fire formed brass measures 1.465". 

My "Loaded" brass measures in two quantities (as I sized two different batches):
250+ measure at : 1.458"
100 measure at: 1.4665"

.223 Headspace SAMMI specs are: 1.4636" min 1.4736" max.

The 100 rounds at 1.4665" is larger than what my chamber is fire forming the brass at.  These were also the rounds that were giving me the original failure to go into battery issue.  In fact, the shoulders are visibly de-formed on the rounds that got "stuck".

Interesting part is that ALL my loaded ammo fits inside a Dillon loaded case gage, but not in my chamber.  I'm thinking now, that I will set the sizing die to resize the fired brass to 1.462", that is .003 setback from the fire formed brass.

Does this make sense?

Commercial Ammo runs fine, I had run some cheap UMC 55 grain loads when I was tuning the rifle up.  Still have some of those rounds, and they got measured this evening also.  They measure in at 1.4585"

Anyone ever run into this issue before?  This is strange.  My chamber is at the very LOW end of the SAMMI spec is what I am seeing with my fire formed brass, and the fact that the loaded rounds at 1.4665" will not chamber without some effort.

I've been using an RCBS AR Series small base resizing die.  I think after this fiasco, I will be ordering a Redding Competition Sizing die tonight.

Respectfully,

Chris

[Agrivere]

High primers are bad. Reseating high primers on loaded ammo is VERY dangerous. One goes off - unlikely to be sure, but still - and you've got a small bomb on your press. Leaving them seated high can lead to slamfires, and possibly even an out of battery slamfire. Possible to blow up a rifle that way. Any ammo with primers above flush should have bullets and powder pulled, and the primer deactivated. Never had to do that but I'm told wd40 will do the trick.

Ok done with doom and gloom. Sounds like you're on the right track. Measuring your cases and knowing what your press is doing is a good thing.   You'll make better and safer ammo that way! Your chamber doesn't sound overly small to me, and your headspace is actually a good bit longer than mine on my national match rifle. My fired cases come out at 1.4610", rather less than yours. Bumping the shoulder back by 0.002" to 0.004" is perfect for a semi-auto. Can even get away with 0.001" on a bolt gun.

So it sounds like you're on the right track! Just be careful with any primers that aren't flush or ideally below the case head!

[navybowhunter]

Thanks, and I hear ya on the hi primers, by HI-primers, I meant just over flush, or canted just slightly.  I wanted to get uniform measurements, and so I re-seated say 15 out of 300 primers, just put them back to flush is all.  My technique on the down stroke.

So, you think I solved it?

Thanks!  I am not a "noob" reloader, but definitely a NOOB and likely a dumbass for never getting that Hornady Comparator.

WOW, what a lesson learned.

R/
Chris

[eagle223usa]

Looking at your numbers it sounds like you found it.  Most of the episodes like yours were too much sizing but according to your numbers it was not enough.

[Agrivere]

I definitely think you're on the right track. Until you start looking at your case necks, seating depth, neck tension, and concentricity! More tools!

I went back and looked at some of the rounds I loaded a while ago that I have kicking around, and egad they are bad. Looking at my old chrono data I was at one time running SD of over 80 in some cases, with an extreme spread of nearly 200 FPS. With proper tools I ran a load yesterday over the chrono and had an extreme spread of 6 FPS and SD of 2.3. Rather an improvement.

Oh and if you want to get a better sizer or seater the Forster die set is IMO just as good if not better than Redding and much less expensive too. That's the set I currently use.

[navybowhunter]

WOW, anything under 12 SD in my opinion is awesome.  I had a 5 group SD of 9 something, with a MV spread of less than 20, weird huh?  I believe more in the SD, it tells the story for sure.

I have had low MV spreads, and very high SD is what it is.

I'll take you up on sizing die recommendations, I have Redding and Whidden seater dies and crimp dies.  I know the value of a GOOD die, especially in the seater/crimp.  Never gave the SIZING die any ANY respect, until last week.

I shoot .223 and .308 for the "fun/work", in the AR 15/10 configuration.  Would appreciate a competition recommendation on a Sizing Die for the both.

I do own "neck" sizing die for my actions that allow it.

R/
Chris

[navybowhunter]

AR-15 JP Enterprises Supermatch .223 Wyde 16" 1:8 Twist, Lapua Match Brass, CCI BR4 Primers, COAL 2.235"                                                
Temp 79   Pressure  29.99    Elevation 115'                                                
Load   S1   S2   S3   S4   S5   S6   S7   S8   S9   S10   Avg Velocity   Factory MV   Max   Min   Velocity Spread   Standard Deviation
77 Moly SMK CFE-223 22.5 grains   2278   2401   2392   2355   2367                  2358.6      2401   2278   123   43.57338637
77 Moly SMK CFE-223 23.0 grains   2442   2398   2461   2496   2429                  2445.2      2496   2398   98   32.6521056
77 Moly SMK CFE-223 23.5 grains *Most accurate, .650 MOA*   2357   2497   2438   2491   2495                  2455.6      2497   2357   140   53.9466403
77 Moly SMK CFE-223 24.0 grains   2531   2532   2559   2540   2557                  2543.8      2559   2531   28   12.02331069
77 Moly SMK CFE-223 24.3 grains   2588   2633   2583   2590   2602                  2599.2      2633   2583   50   18.01554884
77 Moly SMK BLC-2 23.0 grains   2465   2472   2463   2464   2438                  2460.4      2472   2438   34   11.63786922
77 Moly SMK BLC-2 23.5 grains   2552   2565   2553   2545                     2553.75      2565   2545   20   7.189401922
77 Moly SMK BLC-2 24.0 grains *Most accurate .817 MOA*   2582   2555   2569   2570                     2569      2582   2555   27   9.565563235
77 Moly SMK BLC-2 24.5 grains   2622   2626   2617   2613   2603                  2616.2      2626   2603   23   7.93473377
77 Moly SMK BLC-2 24.9 grains   2728   2712   2709   2713   2707                  2713.8      2728   2707   21   7.413501197
77 Moly SMK Benchmark 20.5 grains   2401   2359   2379   2381   2341                  2372.2      2401   2341   60   20.49780476
77 Moly SMK Benchmark 21.0 grains   2510   2509   2438   2407   2464                  2465.6      2510   2407   103   40.13277962
77 Moly SMK Benchmark 21.5 Grains   2502   2473   2504   2506   2546                  2506.2      2546   2473   73   23.27573844
77 Moly SMK Benchmark 22.0 grains *Most accurate .680 MOA*   2568   2543   2519   2571   2550                  2550.2      2571   2519   52   18.84038216
77 Moly SMK Benchmark 22.5 grains   2612   2636   2636   2670   2634                  2637.6      2670   2612   58   18.56448222
69 Grain SMK Benchmark 23.5 grains (Known accurate load)   2876   2815   2854   2821   2826   2768   2841   2811   2828   2845   2828.5      2876   2768   108   27.47089369
                                                
                                                
                                                
                                                
                                                
                                                
                                                
                                                
                                                
                                                
                                                
                                                

[Agrivere]

Might want to try pushing those 77's faster. Not sure if you'll see any improvement but you might. The AMU runs them at about 2750 (I chrono'd some I had at 2736), and Sierra lists their accuracy load at 2600, which is more or less where you stopped. Mine run real well around 2650 FPS. Might not get there with those powders though.

[navybowhunter]

LOL...
"Which is more or less where you stopped".

LOVE this forum, people actually read the stuff.

I did stay to published spec, but am willing to do different things.  VARGET and H4895 are done if at all possible.  Tough to load on the progressive even with all the powder measure mods.

Recommendations for a better flowing powder?

R/
Chris

[Agrivere]

Varget and/or 4895 should definitely work. Don't sweat the powder measure - some of my best loads were loaded on my hornady progressive and I know the loads varied by at least a tenth of a grain.  Many great shooters never weigh charges.

[jmdavis]

Varget, IMR 4895, H 4895, and RL15 are my .223 powders, really any of them do well with .223 (heavy bullets), 7mm-08, 308 and .30-06. There are other good powders, but I pretty much standardize on RL 15 and IMR 4895 for Service Rifle and hunting loads.

The BLC-2 that you have can be great with 60's and 62's.

I like to run 75's and 77's at 2650. For me that is 23.6 gr of RL15.

I'm glad that you figured out the chamber issue.

Goodluck.

[Guardian]

High primers are bad. Reseating high primers on loaded ammo is VERY dangerous. One goes off - unlikely to be sure, but still - and you've got a small bomb on your press. Leaving them seated high can lead to slamfires, and possibly even an out of battery slamfire. Possible to blow up a rifle that way. Any ammo with primers above flush should have bullets and powder pulled, and the primer deactivated. Never had to do that but I'm told wd40 will do the trick.

Please watch. http://www.youtube.com/watch?v=3SlOXowwC4c

Ammo that is not contained in a chamber loses energy pretty quickly. It doesn't take much of a barrier to contain the "bomb."

[jmdavis]

It's bad enough to accidentally set off a primer in the press. But setting off a live round... just the noise is more than I want to deal with.

[Nero]

Varget, IMR 4895, H 4895, and RL15 are my .223 powders, really any of them do well with .223 (heavy bullets), 7mm-08, 308 and .30-06. There are other good powders, but I pretty much standardize on RL 15 and IMR 4895 for Service Rifle and hunting loads.

I'm using 4895, whichever flavor I can get, for both .223 and .308.  (Slightly different recipes for H vs. IMR)  Would love to try RL15 - haven't seen any in ages. 

The OP's diagnosis sounds good to me too.  Also nicer to the brass to minimize the set back by adjusting to your chamber if you're loading for the one rifle.

[Guntuckian]

I like IMR 4895 for .303 British, .30-06, and  7.62x54R.  I like H 4895 for 223/5.56 loads.  I like Red Dot for "The Load"  in all the full size 30 caliber rounds in bolt actions. 

A 7.62x39 bullet loaded in a .303 British case is surprisingly accurate at 25, 50, and 100 yards using Red Dot, with Ed Harris' " The Load" recipe and is great in teaching younger kids, to introduce them to a 30 caliber bolt action without any significant recoil.  On an Enfield, the sights are even almost the same zero as full power rounds!  The brass lasts far longer on these, too.  During the powder shortage, "The Load" recipe enabled me to keep in practice.

Glad that the mystery was solved. 

--gb

[navybowhunter]

For the benefit of all, Cabelas has RL-15 in stock now.

5 pound max on order, just ordered 5 pounds myself.

R/
Chris