Pierced Primer; a powder kiss on the cheek

[sublimaze41]

Testing some loads for increased velocity and accuracy in a Remington .223 BDL. The first load of 25.8 grains H335 behind a Sierra 60 gr HP. 2- five shot groups measures .587 and 0.857 respectively. No obvious signs of pressure.

Next group was 27.1 grains H335 behind previously mentioned bullet. Shots 1 and 2 no problem, shot 3 I felt a sting in my right cheek (Thank God for safety equipment). I never had a pierced primer so I examined everything and no problems were detected. Shot number 4 had no problems. Shot 5 resulted in another pierced primer so I abandoned testing this load.

Of note: OAL was 2.250
Sierra lists 27.1 of H335 as max behind 60 gr Sierra HP
Primers were NOT flattened
Brass was new Lapua
Primers were Winchester small rifle
Obviously, no crimp
The last group measures .0339, to bad it cant be used.

Question? Is this an obvious overpressure issue?

 

[Reloadron]

After a pierced primer I would be looking very carefully at that firing pin actually the firing pin and the bolt face for any signs of damage from hot gasses cutting your metal. You can look at your remaining ammunition, are all the primers seated till they bottomed out? Look for any primers that may be high in the pocket, I like to see .003" or so of depth. From the manuals I have, you are pushing it with those loads. The Sierra 50th Anniversary Edition 60 grain HP H335 min 23.3 and max is 25.7 for about 3,000 FPS. That is about a 25 year old manual. The Hornady 9th Edition for a 60 grain HP H335 min is 20.1 and max is 22.9 for 3,000 FPS. The test rifle for Sierra was a Rem 700 BDL and the Hornady more conservative loads was a Rem 700 also. What was the source of your load data as it seems toasty to me?

Ron

 

[CarJunkieLS1]

That is the reason why you start low and work up. You sir got lucky It looks as if you shot a group of the minimum powder charge and then went directly to the max charge. That is a big NO NO. Piercing a primer at a max load is an obvious sign of over pressure. If you aren't using the exact rifle, rifle, brass, primer, COAL, etc. that they did the testing with then you can't assume that the data they list will be safe in every rifle thats ever been made in that caliber.

OP sorry to be kinda harsh with you, but you are playing with fire.

 

[sublimaze41]

Thank you!
No harshness taken or I would have never posted this.
The Sierra manual was followed exactly from initial load to max dose.
I appreciate the input!

I never exceed book listings but in this case I am guessing I advanced the rate of increase too quickly, I never split the last expected increase appropriately. Apparently the jump of 1.3 grains exceeded the threshold.

Admittedly, I did look through 5 books to find the maximum H335 I could use. This is an older 1/12 rifle that is limited at 60 grain bullets. Looking for the holy grail, maximum velocity with commensurate accuracy.

 

[rg1]

Winchester small rifle is one of the primers not recommended for .223 especially in AR's. In my one bolt rifle with some published data that gets into the 27 grain range with 55 grain bullets, it's excessive in my bolt rifle. I suspect the Win primer and too high pressure with a 60 grain bullet. I trust Hodgdon data with H335 powder. How far to the lands in your bolt rifle with the 60 gr. bullet? May be close or touching in your chamber. Hodgdon says 24 grains of H335 is maximum for a 60 grain V-max and like I said I trust Hodgdon and not a couple bullet companies data. Like already mentioned check your firing pin for flame damage from your pierced primer as if it's damaged you may have more pierced primers.

 

[Rule3]

Considering that Hodgdon lists 24.o gr as max with a different 60 grain bullet and Sierra lists your 27.1 as MAX, I would say it is over done.

How absolutely sure are you of your powder measure weight/scale ???

 

[sublimaze41]

scale is +/- 0.1 grains per check weight.
Max load is Sierra listing, not an internet amazing weight.

 

[Scooter22]

Better a kiss on the cheek than a poke in the eyeball. Hope you were wearing glasses and get the load figured out.

 

[savagemann]

25.8gr to 27.1gr is a pretty big jump without working up to it.
Also, 27.1 sounds pretty high for a 60gr projo using h335.
And, isn't lapua .223 brass quite a bit thicker, reducing it's internal volume?
How full was the case?
I know at 25gr, there is a ton of room left in the case.
I would personally work from 25gr up in smaller increments, as with a jump like that you are most likely missing an accuracy node or 2.