Cool beans, LongRange. Can't wait for your report.
Here's the latest on the firing pin saga. Took the bolts down to the machine shop and pin guaged the bolt head holes in both my BVSS and the subject FV.
Then measured firing pin diameters. BVSS has a .0705 dia pin and .072 hole in bolt head. FV has a .0675 pin and .073 hole. I measured protrusion and found the BVSS at .045 so I decreased the protrusion on the FV to .035. per your suggestion, LR.
I also sent a service request to Savage asking for a firing pin that measures .070-.071.
Any thoughts?
Anyone?
Anyone?
Bueller?
Originally Posted by Texas10
If the FV's measurements are correct it has .00275" around the pin in pin hole which is a bunch. Couple that with the tapered pin tip stopping at .020" or less when it whacks a primer I'll venture to say the clearance is in the .004" or more range around it. Little wonder you're having problems!
Radiusing the pin tip may help but if it were mine I'd be bushing a bolthead.
Bill
Each morning eat a live green toad, it will be the worst thing you'll have face all day.
like Bill said i dont think anything you do is going to help the BVSS with the .0675 pin and .073 hole thats a pretty big gap around the pin even if you radius the pin...both my rifles have PT&G bolt heads and the long action pin measures .067 and the hole measures .069...i just measured the factory bolt head hole from my short action and it measures .072...im measuring both with calipers so the holes may be + or - a little...im going to shoot a couple of rounds through the long action today before i mess with my short action because it shoots so well but it does blank just a little.
so i fired 6 rounds about an hour ago after radius-ing the pin and as you can see its 99% better...
2 cases on the left were fired last weekend before doing the work to the pin....48.5g H4831sc with a 142g smk and the pin set at .032
the 2 cases on the right were fired today with 49g H4831sc and a 142g smk with the pin set at .023 protrusion
the case in the center was fired today same load as above but i decreased the pin protrusion by a 1/4 of a turn..not sure what the protrusion measurement was as i made the adjustment in the field today after shooting the first 2 rounds then set it back to were it was after firing this round.....
i didnt take a before pic but will when i do my short action...heres the bolt after shooting today...and thanks for the info BillPa you saved me a $160 bucks and a long wait!!
Quite clearly firing pin dia vs hole dia is a factor here, as is firing pin tip radius. The radius of the factory pin tip must be in the area of .034 but if the pin is only protruding .020, that leaves .014 still in the head when the primer cup is trying to crawl up the pin and into the head. I don't know the math to figure out the radius gap that is on top of the clearance caused by tolerance stack between the pin and the head, but it must be playing into the scheme.
BTW: why replace the head if replacing a cheap firing pin accomplishes the same thing?
The pin on my BVSS and the FV appear the same, and part finder lists the pin as costing $2.00.
The interesting thing is that the serial number for the FV does not exist in Part Finder, which makes it hard to order a part. In fact, the latest serial number in the system is J662160 which leaves several thousand numbers not accounted for.
If your referring to my bolt head this rifle was a 300wm its a 260AI at the moment...I replaced the bolt head in my short action because I replaced the bolt body as well and figured might as well...at this point I'm glad I did because the hole in the factory short action measures .072 and the PT&G is .068.
if you can get a larger diameter pin that's the way to go if not bushing the bolt head you have would be better than buying a bolt head from PT&G as they reaised the price of them.
IIRC when you reworked the tip you checked it @.025" protrusion, the reason I think I'm still seeing some cratering and some clearance on the pin fit. The tip should almost completely fill the hole or close to it @ .020" and set the bench protrusion @ 30-30. like this.
So, round off the tip a bit more and recheck it at .020".
Oh, and a thanks is unnecessary, gratuity on the other hand!
Lemmie know how ya make out.
Bill
Each morning eat a live green toad, it will be the worst thing you'll have face all day.
So your saying round the tip more at the peak and check as I'm going and at .020 stop and then set the protrusion to .030? I radiused the pin in my short action this weekend and have it set at .019 and the hole is pretty full should I adjust it out 1/4 turn?which will make it right about .025-.028IIRC when you reworked the tip you checked it @.025" protrusion, the reason I think I'm still seeing some cratering and some clearance on the pin fit. The tip should almost completely fill the hole or close to it @ .020" and set the bench protrusion @ 30-30. like this.So, round off the tip a bit more and recheck it at .020". Oh, and a thanks is unnecessary, gratuity on the other hand!
Lemmie know how ya make out.Bill
Last edited by LongRange; 02-02-2016 at 09:14 AM.
I think maybe I'm confusing you. Forgive for the crappy pic but....
There I have the pin assembly clamped in a vise and the bolthead just set on top of it with protrusion set to .03455" (.035") from the boltface to the tip of the pin or what I call the "bench" protrusion setting. When checking an as-is or a re-profiled pin tip I use the same setup but set the protrusion to .020". That way I can see how much or little clearance there is between the tip and pin hole.
If you look back at the pics of the pins-bothhead I posted earlier its what I'm looking for, the amount of clearance between the two pins. I haven't found a way to accurately check the amount clearance so I just get a close length measurement from the tip of the pin to it's shank. If that length is .020" or less I assume the full diameter of shank is in the pin hole when the pin strikes a primer.
Clear as mud?
Bill
Each morning eat a live green toad, it will be the worst thing you'll have face all day.
I called Savage Customer Service. They would not "hand pick" a firing pin for me, and I could not buy a quantity of them to sort through myself. I could buy just one, but i'd have to sign a waiver.
They were also concerned that the problems I was seeing where while shooting hand loads, so I said "fine, I'll shoot some factory loads and include the spent casings when I send it back for warrenty repairs. Just trying to save you a buck".
I set the firing pin protrusion back as LongRange suggested and shot several rounds each of 4 different factory ammo. Got the same results, cratering and piercing.
Big brown truck should arrive today to take it back for another "shot" at making it right…he-he.
Texas10 im interested to hear what they do and if it resolves the issue.
i get what your saying now.I think maybe I'm confusing you. Forgive for the crappy pic but....
There I have the pin assembly clamped in a vise and the bolthead just set on top of it with protrusion set to .03455" (.035") from the boltface to the tip of the pin or what I call the "bench" protrusion setting. When checking an as-is or a re-profiled pin tip I use the same setup but set the protrusion to .020". That way I can see how much or little clearance there is between the tip and pin hole.
If you look back at the pics of the pins-bothhead I posted earlier its what I'm looking for, the amount of clearance between the two pins. I haven't found a way to accurately check the amount clearance so I just get a close length measurement from the tip of the pin to it's shank. If that length is .020" or less I assume the full diameter of shank is in the pin hole when the pin strikes a primer.
Clear as mud?
Bill
FWIW, CCI 400 primers are kinda soft. I had to go to WW and Wolf primers to better contain my 223AI pressures.
I agree, primers do come in various flavors. FWIW I find Winchester primers to be a little softer than CCI 400, and that is one reason I switched from WW to CCI. I do shoot identical loads in both my model 12's, and in my BVSS I only see cratering at very high velocitiy loads. I've never experienced a pierced or blanked primer in my BVSS, even at half a grain over max book load when working up a new load.
I also have magnum primers and benchrest primers to try out. I believe that both of those have slightly thicker cup materials and will be less likely to blank or partial blank. Interestingly, none of my blanked primers exhibit any flattening, which leads me to believe that this is definitely a firing pin fit/clearance issue.
Tex, here Greg Tannel (Gre-Tan) explains the causes of cratering-blanking and how to fix it.
https://www.youtube.com/watch?v=-CDJKLp7BsI
Bill
Each morning eat a live green toad, it will be the worst thing you'll have face all day.
Great video, Bill. Thanks for sharing that. I get what he is saying about support behind the primer, and with higher than normal operating pressures, his fix is probably the best one. Personally I like the idea of a tighter fitting firing pin vs one that is rambling around inside the head as it is slammed forward.
However the bolt head hole in the subject model FV is only .001 larger than my BVSS which has no issues with cratering at normal pressures (Holes were measured with precision pin gages) so I'm unconvinced that a larger hole is the issue in this instance. But with .0055 pin to head clearance in the FV as compared with .0015 in the BVSS that is shooting well, my first avenue of pursuit is trying to get a larger firing pin for $2.00 (or free under warranty). Second would be a new bolt head for $29.00 (maybe free too?) but I'd likely have to re-set the head space, and I don't have the wrenches or vice. So hopefully with the gun back at Savage, they'll fix this issue and my son can go back to shooting really tiny groups with it.
As a follow up, while mess'n around in the shop the other day I had a brainstorm (brainfart?) and thought how hard can it be so I made this...
Looking at a few primer dimension charts the largest cup diameter was .2120" so faced a chunk of bar off square then pre-drilled it with a #2 bit and finished it to .250" x .300" deep with a .250" end mill bit. I made the bushing using the shank of a G8 bolt to .252" OD"x .330" long for a interference proud press in fit. After pressing the bushing in I drilled the pin hole to .062"(1/16") and faced it flush.
Thoughts?
Bill
Each morning eat a live green toad, it will be the worst thing you'll have face all day.
That's perfect, Bill
If I had a Mill, I'd be doing what you did instead of sending it back to the factory
Ream to fit after pressing the insert in or let the press fit shrink the hole to a close fit. Either way, fixes the issue perfectly in my book.
What's optimal, half thou clearance? Full thou?
Just to catch y'all up on what's going on with this new model 12fv blanking primers issue. Factory has had it about 10 days when I called earlier this week, and nothing had been done, and they'd never linked up the online service request with the gun, so it was sitting at "the range" for test firing ( I had enclosed as-fired brass from factory loads that exhibited blanked primers).
Service tech stated that they were weeks behind on the email system, and she was "closing the tag" on this issue.
I asked her to please copy my email to the techs so they might have some idea where to start. I should have included that with the gun, but neglected that little detail.
BTW I see the 100 dollar rebate is on again for ANY model 12. Woo-Hoo! Cabelas here I come!
Stay away from cci 400 primers and use cci 450 or cci br instead. Your problem will most likely go away. 400 primers have very thin cups. Primer cup hardness is also a factor.
http://www.jamescalhoon.com/primers_and_pressure.php
Last edited by kkeene; 02-26-2016 at 10:46 PM. Reason: Added more info
Big brown truck arriving today, unfortunately Savage failed to do anything to fix the blanking problem. The reason? They never connected the email chain to the gun and were clueless as to what the problem was. Even though I enclosed spent brass with blanked primers. They shot it and boxed it up without ever trying to contact me or look into the CS database. My subsequent phone call was apparently an hour too late to link my service request to the gun.
The gal in CS apologized and is sending me a firing pin, no charge. I am faxing them a waiver incase I need to order additional firing pins until I get one that fits properly.
She did go to the "gunsmith" to ask about changing the firing pin to one that fits better. The answer was "you can't change the size of the firing pin". I said that I don't want a custom made firing pin, I just want one that is made to the nominal print dimension, and not one that is out of spec.
Am I being stupid? This seems like it should be a really simple process, yet it failed miserably.
Maybe next time I'll enclose a burner phone and have the GS call me directly.
Gun arrived today, bolt was in the fired condition and wouldn't install. Probably triggered in shipment.
Anyway, unscrewed the BAS and reset the fireing pin. Going to wait until new firing pin arrives and see if it fits the bolt head better.
Last edited by Texas10; 03-01-2016 at 05:17 PM.
You don't need to disassemble the bolt to reset the firing pin. Just catch the button on the edge of a bench and push the bolt down.
New firing pin arrived yesterday. Measured .002 larger in diameter than original, so installed and set protrusion to .033".
Loaded some rounds to same receipe that exhibited the problem with blanking, and shot them today.
Problem solved. Only showed some partial blanking at max load, no full blanking (pierced primers).
Thanks for all your good advise, guys. Really appreciate your experience and knowledge and willingness to share.
Today I ordered 6 new firing pins, hoping to get one that fits with less than .002 clearance. Asked the Customer Service rep if he had the drawing available to see what the tolerance was on the pin dia, but he had no idea what to look for and couldn't share with me the details if he could find it.
Does anyone here know what the min-max diameter is for the magnum pin? Bolt head has a .073 hole and I'm hoping for something in the .070 to .072 range. I can always reduce a too large dia pin. Adding metal is a bit more problematic.
Ordering 6, hoping to get one the right size is probably nothing more than a crap shoot. The hole size on the bolt head has a range from.072" to .075". The firing pin tip is .068" to .071". That's what the print says anyway, but that doesn't mean that they stick to it.
"As long as there's lead in the air....there's still hope.."
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