Okay guys, I have put together a 338-06 with a Adams and Bennett barrel and a older flat-backed model 111. I have taken it to the range twice now and put roughly thirty rounds of handloads down the tube. Each of the times, I have had one misfire. It appears to be a light primer strike and I did inspect the rounds and did fire them. For the record, they both shot into the same group so I do not believe it to be a loading issue. I am concerned with this as I plan to use this rifle this fall on elk. What things can I do to pinpoint the issue?
If it is a light primer strike it's pretty easy to diagnose.. really not many culprits could be responsible... weak spring, firing pin wear or size problem, case seating to deep in chamber or looseOriginally Posted by Bearlodge10
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Bingo! What Ted said.
Thanks guys, so rookie question follows suit. How do I determine if it is a spring/firing pin issue or one of chamber dimensions?
If it's first time firing, it's most likely a case sizing issue resulting in too much headspace. I've never encountered a weak firing pin spring, but insufficient firing pin travel will cause misfires.
"As long as there's lead in the air....there's still hope.."
In both cases, the misfires occurred well into the range session. Probably round 12 and 4 respectfully.
It is really easy to over size your cases so I would look into that and check your firing pin protrusion. I would also listen to everything "sharpshooter" has to say.
If you hand load and do not have a way to check the case dimension from base to shoulder of the case(case head space) this is more than likely your issue. You should be .003" or less within a fired case head space dimension. If you have fired cases where the primers are proud, this is another sign your cases are shorter than the chamber.
The Dunning-Kruger effect is alive and well.
My first thought was case headspace too.
We assume the barrel was installed using proper headspace gauges (both go & no go).
A simple test for your sized cases is layer "Scotch" tape on the case head. A good rule of thumb is you will feel resistance after only two layers (approx. .004) when you close the bolt. If it requires many more layers to feel resistance than the cases may be sized down too much. You shouldn't be able to close the bolt at all after 6 or 8 layers, if it takes that many the cases are way too short for the chamber and most likely the cause of the FTF.
If you have a case length comparator or means to measure shoulder to base of the fired cases to the sized ones you will be able to also see if they are oversized (too short base to shoulder).
Final thought is to thoroughly disassemble & clean the bolt.
Then check the firing pin protrusion should be .035 - .055.
My .02,
Randy
Sorry Robinhood, I was typing while you posted and we essentially said the same thing.
Never a problem, your choice of words are normally an improvement over mine.
The Dunning-Kruger effect is alive and well.
I appreciate the help. I will run the "tests" this evening and report back.
Robinhood: "If you have fired cases where the primers are proud, this is another sign your cases are shorter than the chamber." By this, do you mean that the primer is pushed back out of the primer pocket such that the primer protrudes out? If so, that is not the case.
I just completed the steps suggested by mnbogboy with the scotch tape on the case and closing the bolt. I get resistance after two layers of tape and at five layers, the bolt wouldn't close. I did this with the dummy round I put together when setting my reloading dies as well as with a resized case. I also measured the firing pin protrusion using the depth gauge on my calipers and got .061. I also disassembled the bolt and cleaned it. There was a little bit of gunk and some rust but nothing that I felt was alarming. However, truth be told that is the first bolt I have cleaned so take that for what it is worth. I am leaning towards a sizing issue with regards to the shoulder. However, I think I need to load another box and go to the range to see if I have more issues.
Rust & gunk could have cause your problem, especially when the spring and pin are involved. Saw the same on a friends 700 once. Hopefully that was it.
Couple other things;
Were the misfired primers before you shot them dented normally?
Is this a new/different lot of primers?
Is there any possibility of primer contamination? (Several years back I had two ftf in the same lot I loaded...narrowed it down to sweat off my brow or sneezing!
Year's ago (40 or so) I loaded some wet cases. Had a couple of FTF that cost me a buck. They rest dried on their own and fired a month later.
Is this new brass? And has the primer pockets been uniformed? Some brass has a radius in the pocket bottom that interferes with good seating, poorly seated primers can and will cause ftf.
Just a few thoughts.
Make sure that primers are seated fully.
Were the misfired primers before you shot them dented normally?No, definitely lighter strike or shallower dent
Is this a new/different lot of primers? yes, but I loaded for two other rifles and so far no issues with them
Is there any possibility of primer contamination? Hmmm, you might have something there. I did anneal these using a torch and water to quench. However, I didn't load them until the next day or the day after that.
Is this new brass? yes, annealed and necked down 35 Whelen brass, primer pocket not uniformed. I did decap these and see no difference in the pocket or the flash hole
Last question, in putting bolt back together, I wiped everything down with Hoppe's lubricating oil and let it sit for a few minutes then wiped down the excess so there was just a light sheen and then put back together. Was this too much, not enough??
To me all appearances are pointing to the "dirty" bolt or other mechanical problem as first thought because of the light strikes. You have established that case headspace appears to be within reasonable limits for reliable firing pin contact.
A couple more thoughts;
1. Did the ammo the fired normally have "normal" or light strikes also?
2. In the course of your build was there a stock change or stock work like pillars or bedding?7 Bedding or even the notch in the rear pillar could cause a slight "drag" on the sear slowing the firing pin fall.
3. Without any change I have in the past had the front action screw contact the bolt head slightly without noticing it after torque until accuracy changed. With a case in the chamber the bolt head may be pushed a little upwards. This in effect may cause again more drag on the firing pin. This is easy to check by coloring the outside of the right bolt lug with a Sharpie and then cycle the bolt.
In answer to bolt lubes, as a rule I do not lube mine only wipe parts with a lightly dampened rag. Others on here may have other opinions which is good.
I think what you did will be ok.
You might test your results with just primed cases. The primed cases only should "dent" overly deep because no internal case pressure will be holding the pin back. $4 worth of primers will certainly tell you if it might happen again.
Good luck and keep us posted
Bearlodge, without more information on the history of the rifle everything is a shot in the dark..
Is this rifle new or preowned/used?
Did it fire every time before you changed the barrel?
If used, do you know any history of the bolt being adjusted to improve the bolt lift?
Have you ever altered the bolt or firing pin settings to improve bolt lift or firing pin protrusion?
Sharpshooter focused on firing pin travel........
When you cock the rifle after it has been fired, does the cocking force begin early in the motion with the bolt just starting to be lifted or do you pull up a a good distance before the cocking ramp is engaged? This tests the cocking piece position relating the the cocking ramp of the bolt body. The cocking piece pin should be off the bottom of the ramp in the fired position but probably no more than .020" . This is the beginning of ensuring you have enough firing pin travel. Sufficient firing pin travel is needed to provide enough energy to ignite the primer.
Is the firing pin protrusion more than .045"? If the cocking piece is in the correct position and the firing pin protrusion is correct(.035"-.044") you can be certain the firing pin travel is sufficient. This will provide the energy needed to ignite the primer.
Does the cocking piece sleeve slide back and forth over the cocking piece with ease? This sleeve if mishandled can collapse or get "tweaked". The cocking piece will ultimately travel about 1/4 inch through the sleeve as the firing pin is released to strike the primer.If this motion is impeded, this will reduce the energy the firing pin needs to ignite the primer.
When you assembled the bolt did the firing pin assembly slide back and forth with ease? Sometimes people don't ensure the axis of firing pin hole in the cross pin is in the same axis of the firing pin itself causing it to drag through the hole as it travels towards the primer. This will reduce the energy the firing pin needs to ignite the primer.( I will compress the wavy washer by pushing on the bolt head to allow the cross pin to self align as the firing pin slides back and forth.)
Does the firing pin slide with ease through the bolt head? Is there anything causing the firing pin to not move freely? If there is, your firing pin may not have enough energy to ignite the primer.
When all of these issues are verified untrue or resolved and you still have issues. Try a different brand or batch of primers. Insure the primers are seated correctly. Make sure all of you cases have been sized to within a close tolerance to the chambers dimension. The should not vary more than a couple of thousands(.002") max.
The Dunning-Kruger effect is alive and well.
Is this rifle new or preowned/used? Used rifle
Did it fire every time before you changed the barrel? I never shot it with live rounds only with snap caps to ensure functionality
If used, do you know any history of the bolt being adjusted to improve the bolt lift? No known history of the rifle, does not appear to be any alterations to the bolt etc.
Have you ever altered the bolt or firing pin settings to improve bolt lift or firing pin protrusion? Other than the cleaning I just did. I have not made any changes
Sharpshooter focused on firing pin travel........
When you cock the rifle after it has been fired, does the cocking force begin early in the motion with the bolt just starting to be lifted or do you pull up a a good distance before the cocking ramp is engaged? I have honestly not "measured" this travel. However, I have two other savage bolt rifles (Stevens 200 and Savage 111) and have looked at and compared bolt travel lift etc. in these compared to the one I have issue with and can't see or feel any difference.
Is the firing pin protrusion more than .045"? Measured at .061
Does the cocking piece sleeve slide back and forth over the cocking piece with ease? This is there there was a little rust and gunk when I did the disassembly and clean. there was movement there but better afterwards
When you assembled the bolt did the firing pin assembly slide back and forth with ease? Yes
Does the firing pin slide with ease through the bolt head? Is there anything causing the firing pin to not move freely? Yes. I can't see or feel any obstruction
At .061" You have lost .026" of travel. Adjust the firing pin protrusion to .035 with a max of just over .040. The pin stop locks with the washer every 1/4 turn. Every quarter turn of the pin stop is .009". This means you can get between .035 with the highest you should have to go would be around .043".
Go back and remove the cocking piece from the rear end of the firing pin. Clean and polish the outside of the cocking piece and the inside and outside of the cocking piece sleeve. Clean and polish the inside of the bolt to the best of your ability. Flush and dry all components. Drop the cocking piece in the the sleeve. It should slide through with no impediment. If true then reassemble the firing pin to where the cocking piece pin is just above the bottom of the cocking ramp maybe .020" - ..030"
When you reinstall the bolt dry fire the weapon then take your finger, starting with the bolt in the closed position, lift the bolt. It should begin to cock the bolt a short way from the closed position.
Test.
If this does not resolve the issue it is you primers or your sizing on the cases that do not fire.
The Dunning-Kruger effect is alive and well.
Thanks to all your help guys! I reloaded 20 rounds with primers from a completely different box then took it to the range. I only got through 10 (due to weather, time and dedication to ladder tests with different rifles) and had no issues. I am beginning to believe that I might have a bad batch of primers as I had 1 FTF with a different rifle. Upon review of my reloading log, I see that both the batch of .338-06 and the .308 were loaded on the same day and I know that those had to be loaded with primers from the same box.
Robinhood, I will take your suggestions and keep them under my hat until I see further issue. As stated above, I believe that I had a primer issue and not a bolt issue. Your numbers and steps are good to know and have a bolt that I can mess with to see impacts of such changes.
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