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Topic: riddle me this ole wise one's (Read 434 times) previous topic - next topic

riddle me this ole wise one's

I finnaly got to shoot my 6.5x284 today... had 20 loaded up for break in with 51 gr. of re 23 under a 147 eldm… according to Hornady 52.5 gr. is max load... these 20 are loaded in Hornady cases... I chamber the first one and it chambers as it should and I let it fly... went to eject it and had heavy bolt lift and the bolt wouldn't open... had to take a cleaning rod and plastic mallet to knock the bolt open... wth… first shot and I gotta beat the bolt open.. so I clean the barrel and chamber another one and same thing... stuck bolt... so now I pull a round apart and weigh the powder... was dead on 51 gr. according to my new scale... so I start checking everything... head space is good.. .004 growth from new to once fired brass...run my bore scope in it and everything looks good as it should in a new pipe... so I clean it again and load one with 49 gr of powder..3and a 1/2 gr below book max and let it fly... same thing.. heavy bolt lift and had to tap the bolt open... heres where it gets interesting... I had some once fired nosler cases ready to load and charged one with 50 gr of same powder and let one fly... bolt lift was fine and opened as it should... so I load one with 51 gr. same thing bolt opened as it should and ejected the round with no problems... so I start measuring things on both cases... outside neck diameter the same for both cases... measurement above the rim the same on both … shoulder to base the same on both... only thing I could find different on them was oal of the case and the rim diameter.. the rim on the nosler case was .003 bigger than the Hornady and the oal was .005 longer on the Hornady... but still .005 below book max length... I dunno… got me puzzled for sure...
Grant

Re: riddle me this ole wise one's

Reply #1
Case volumes? Nosler might have more volume.
Any oily residues on brass or chamber? Even water, rain or snow?
I would say primary extraction but the hard lift rules that out.
My first thoughts
11X Grandfather
Part time Savagesmith

Re: riddle me this ole wise one's

Reply #2
not sure about volume but both cases are almost identical in weight.. no rain or anything like that... chamber is clean and dry cases are clean...
Grant

Re: riddle me this ole wise one's

Reply #3
Case weight doesn't always correlate with volume. H20 volume difference may account for the "pressure" difference.
Any unusual primer visuals?
Any unusual marks on the brass?  Maybe a "rough" chamber combined with new soft brass caused the sticking.
The bore itself may be a hair on the tighter/rougher side. Even after a few shots it may be smoothing out. I imagine your first shoot & cleans did show the usual copper pick up.
11X Grandfather
Part time Savagesmith

Re: riddle me this ole wise one's

Reply #4
Can you compare your new scale to your old one? Or with a check weight?  ( guessing you probably did )

Re: riddle me this ole wise one's

Reply #5
I checked the weight on a fx120i scale. I might buy volume difference but not when 3 and a 1/2 gr less charge sticks with the hornady.its something to do with that hornady brass. None of the issues with the nosler brass. The barrel is a new shilen select match barrel. The chamber is smooth as a babys but. No scratches or burrs or anything like that. First round down it. I am going to trim .010 off the oal of one of the hornady cases and see if that changes any thing. Like I said its already about .005 short of book max oal.
Grant

Re: riddle me this ole wise one's

Reply #6
I'm running out of ideas for you. There are a couple more things but you've probably ruled them out.
1) Distance to the lands? .010 or more
2) And back to the primary extraction.  Does this action have the original bolt (and all its parts including handle, rear baffle, bolt body and bolt head)?  Were the bolt lugs trued or lapped?  Reason is small changes can throw off the PE timing or eliminate it all together.
Combine this with "heavy lift" possibly from first couple of "green" barrel shots.

Hope you get it solved soon so you can have fun with it.
11X Grandfather
Part time Savagesmith

Re: riddle me this ole wise one's

Reply #7
Grant, case capacity on Nosler brass tends to be a little lower than Hornady’s. But since the Nosler brass was once fired and I’m presuming not FL size, the capacities should have been very close.

Were the necks turned in the Nosler brass?  I’m wondering if the necks on the Hornady brass are thicker and the leade in your chamber is tight leading to excessive pressure with the Hornady brass that wouldn’t occur with the Nosler brass if the necks were turned. I’m really fishing out in left field here but ....

Re: riddle me this ole wise one's

Reply #8
mn it has the original bolt.. only thing I changed was the bolt handle... if it was something like that it would do it with either case... jerry the nosler brass was fl sized with a Hornady fl sizer...necks wasn't turned... both cases have the same od neck dimensions after they were fired... that's the part I don't get... I measured everything I could think of on both cases and every thing measures the same on both except the over all length of the cases and the rim of the base...… im thinking the over all length of the case is too long even though its a few thousandths shorter than sammi max...going to go out after while and do some more investigating with this ...
Grant

 

Re: riddle me this ole wise one's

Reply #9
Following up on the neck, the fired cases measure the same but do the necks measure the same loaded?  wall thickness may be the culprit.

The once fired Nosler brass may have a little more springback thus letting it extract. 
The bolt handle change can affect PE. A good test is to place a feeler gauge between the rear baffle and receiver.  If you can get one of the empty fired Hornady cases to stick you may want to try this test just to eliminate the primary extraction.

Did the stuck brass have smileys?
11X Grandfather
Part time Savagesmith

Re: riddle me this ole wise one's

Reply #10
No smileys that I can see.
Grant

Re: riddle me this ole wise one's

Reply #11
It's the brass 😁 seriously though I found my old speeds from a 10 shot velocity test.

50.6  2892
50.8  2922
51.0  2929
51.2  2942
51.4  2953
51.6  2966
51.8  2961
52.0  2982
52.2  2995
52.4  2992

147 eld m, RL 23 and Lapua brass
Dave

Re: riddle me this ole wise one's

Reply #12
Early on you mentioned they chambered as usual.
Meaning not snug.  In the past I have headspaced once in a while a hair on the tight side and was not able to size that tight(without shell holder mods).  If the cases chambered tight,  I ended up with hard bolt lifts (no place for the brass to grow).  Being you started with new brass my guess that was not the case. But certainly worth accessing.
I have been guilty of using cases for head space gauges and don't advertise or recommend it.  It works in combination with a little luck & common sense.  Worst case is you can end up too tight.  You probably used a go-gauge which is correct.  Of coarse a tight go gauge or worse yet out of spec one could get you there also. Long story short your new & sized brass should fit "loose" in your chamber.

No smiley evident and all load data below max makes me think it is not pressure.  But rather a brass issue as you originally thought.  Did you compare the case head to shoulder dimensions of new brass, Hornady fired, sized Nosler and fired nosler?
I believe a 9mm or 10mm 3/8 drive socket placed over the necks will serve as a fixed datum for measuring shoulder to case head.  The number you come up with on overall will let you compare the lengths within .001.  I use this method all the time for setting bump and it's almost foolproof.  You might have a fancier tool but those measurements might help in solving the problem.
11X Grandfather
Part time Savagesmith

Re: riddle me this ole wise one's

Reply #13
I get it....that old Hornady brass feud...lol
11X Grandfather
Part time Savagesmith

Re: riddle me this ole wise one's

Reply #14
I did two rl 26 tests, the speeds are a little faster on the second test but we're 3 shot groups not a 1 shot velocity test.

Test 1.                          Test 2

51.6  2842
51.8  2844
52.0  2838
52.2  2861
52.4 2871.                   52.3  2874   SD 15.2  ES 33
52.6 2872                    52.5  2887   SD 3.9.   ES 9
52.8  2893.                  52.7  2898   SD 16.6  ES 36
53.0  2889.                  52.9 2914    SD 8.3.   ES 20
53.2  2914.                  53.1 2922    SD 11.1  ES 26
53.4  2920.                  53.3  2935   SD 7.9    ES 19
                                   53.5  2939   SD 2.4.    ES 5
                                    
 
                           
Dave