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Just got my 20br together and finally had a chance to shoot it. It is very difficult to extract fired cases. Even at 28.5gr Varget under a 55gr Berger it is more difficult than I have ever felt. Todd Kindler told me this is a very very weak load so it should not be a pressure issue. Sized cases cycle fine. The only measurement I see a difference between sized and fired cases is about .002-.003 shoulder bump and the neck goes from .233 to .235 in a .236 chamber. I am at a loss.
is the chamber dirty or ruff?
Not that I can tell. I tried cleaning it just in case. I did just discover that I can not easily slide a bullet into a spent case. Could this be a result of or a clue to my problem?
Make sure the front action screw isnt too long.
I had this happen with my 6br. The action screw was too long and when a round was chambered the bolthead would ride up on the long action screw(basically pushing the case to the top of the chamber). Once it was fired the bolt did not wanna lift because the brass fireformed to the chamber that way . An unfired case would go in just fine, but a neck sized formed case wouldnt chamber cause the first firing deformed the brass(ruined 15 pcs of Lapua brass before I figured it out).
May not be your problem, but thought I'd mention it so you dont have to find out the hard way like I did. Only had to take a smidgen off the bolt too. Just next round you fire try to loosen the screw and see if it frees up the bolt.
There seems to be mixed opinions on this on 6mmbr.comQuote:
Originally Posted by rfurman24
Thanks. I had already checked that. It cycles like a dream until I fire it or try to cycle spent cases. Cycles sized case perfect.Quote:
Originally Posted by pdog06
Is the hard extraction lifting the bolt or after the it rotates all the way, but won't move back to extract a case? I assume if you re-chamber a fired case ( not resized) it also extracts hard?Quote:
Originally Posted by rfurman24
One other thing. Take a look at the casehead(s) of the fired brass and see if there are any rub marks about 25% around midway between the primer pocket and rim, usually right on the headstamp.
I'm just fish'n and trying to eliminate some possibilities. Let me know.
Bill
Bolt lift is more difficult than I think it should be but my main concern is actually pulling the bolt back. I do not see anything wrong with the brass maybe slightly more shiny around the primer area.
Post a picture of some fired brass.
Chamber probably just needs polished.
Ok, some more fishing. Using one of the hard extracting pieces of brass place a shim, maybe .005-.010" between the rear baffle and the receiver then try it. Two-three pieces of paper, something on the order of printer paper will work.Quote:
Originally Posted by rfurman24
What happens then?
Two or three pieces of scotch tape will work as well.Quote:
Originally Posted by BillPa
The paper trick did not help. The rear baffle does not even touch the receiver on primary extraction. The brass looks like crap I will have to post pics tomorrow.
Then you have problems!Quote:
Originally Posted by rfurman24
When the bolt is opened the lug on the bolt handle must contact the cam on the rear baffle otherwise you have zero PE. The baffle may be loose when the bolt is closed, but when its rotated to the open position the lug on the handle will contact the cam, push the baffle forward till it contacts the bridge, the handle contacts the cam and the bolt is forced rearward.
Two conditions can exist, too little of too much PE. Too little means the cartridge will not be pulled free of the chamber, the start of the extraction process making extraction hard. The other, too much and the will lugs will still be engaged while the PE cam is trying to force the bolt back, they're fighting each other.
Actually, there is a third condition, it correct and you have .060-.070" PE
If in fact the baffle isn't contacting the bridge when the bolt is opened there is a problem.
Bill
Sorry, Bill, It does make contact will extracting a shell. The tape still does not help.
any swelling about a 1/2" up from the base?
Found out my 6mm redding die was to large down there. and I have to run my brass through my 7mm rcbs die to size that area until I get a different 6 mm die.
I have tried sizing with my 20br and 22br dies. Same problem.
Ah.. OK, but another question. You say the bolt rotates all the way open without undue effort, but it tough pulling it back. If thats correct how do you get it open, a bump on the bolt handle, a good sharp smack or a BFH?Quote:
Originally Posted by rfurman24
Bill
Bill, it is more difficult than I feel it should be lifting the bolt at the top but my concern is the difficulty pulling the bolt back. I have to pull very hard to get it back after firing.
Okay, I have an idea.. Try a different powder with a different load and see if the same condition exists. Post back with your results.
Well, I dunno. This is what I hate about long distance gunsmith'n. If I had it "in hand" I guess it would take a only few minutes and a beer ( or two) to figure it out. I still think its light on the PE, but without rip'm the barrel off and measuring its only a guess.Quote:
Originally Posted by rfurman24
Anything else done to that action other than the new pipe?
I bought it, shipped it to Fred and he timed and trued it and installed the barrel.
Okay, Bill, The tape did nothing. But since you though it was PE I used a .025 feeler gauge and stuck it between the rear baffle and the action. With a fired case bolt lift is very difficult but the bolt actually slides open with ease.
A different bolt did not help
Yeah, and it may or not, its why Fred says sure they'll probably fit, but not be right.Quote:
Originally Posted by rfurman24
"I used a .025 feeler gauge and stuck it between the rear baffle and the action. With a fired case bolt lift is very difficult but the bolt actually slides open with ease."
OK, the initial bolt lift is one thing, the extraction is another.
One thing with the .025". Did it cycle normally without a cartridge and the .025 shim? What I'm looking for is too much PE with the shim, the lugs and PE cam are engaged at the same time. What you'll see if that happens is some resistance the last bit of bolt rotation at the top and/or some hard resistance closing the bolt.. You could try a bit more shim, but try cycling the action without a cartridge just to make sure you didn't go too much.
As far as the bolt lift is concerned that can be a number of things. Lets get the bugger pop'n the brass out then toss some ideas around to address that.
Bill
I cycles fine with no cartridge and the .025 feeler. As a matter of fact little to no pressure is put on the feeler with no cartridge. I took the barrel off, inspected everything(I found no problems), and reassembled(resetting headspace). Still no luck. I think is going to have to go back to Fred.
Quote:
Originally Posted by rfurman24
Hummm.......050"+ .025" = .075"...thats about right..
If you want to measure the amount PE, pull the barrel, close and lock the bolt then take a measurement from the receiver face to the bolt head. Next, unlock the bolt, but keep it pushed fully forward then take a second measurement. The difference between the two is the PE. BTW...Make sure the bolt handle isn't making contact with the sides of the notch in the receiver when the bolt is closed.
Was the bolt handle changed out with a custom per chance? Any other parts changed out?
Bill
Sounds like the chamber is too tight to me. You say Fred installed a new barrel, was it a pre-fit? They are likely chambered from the barrel maker not Fred. Add as much shim as you can with an empty chamber and still have a functioning rifle. Fire a round and use that shim, it should come out easily. If not, the chamber is too tight. A sized case works fine right?
I am not understanding what you want me to shim. I still has a little more effort required to open the bolt on a sized case than I think it should. Even though it is t&td it is a little more difficult than my other savages. After talking to Fred today I think the chamber is too tight as well.
have you tried lube on the case, my ar-10 is very tight on extraction but a touch of gun oil or lube on the unfired round keeps it running nicely. kinda leaning towards that polishing suggestion, but the lube will tell you if your going in the right direction w/ that suggestion.
Like I said before, extraction and bolt lift are two different animals.Quote:
Originally Posted by rfurman24
If the bolt slides open with ease it means for what ever reason the PE is on the short side. Why, I don't know, you'll have it checked and corrected.Quote:
I used a .025 feeler gauge and stuck it between the rear baffle and the action. With a fired case bolt lift is very difficult but the bolt actually slides open with ease.
The hard lift could be caused by a number of things and without having the rifle in hand all you, I and everyone else is doing nothing but looking over the Chinese menu of fixes. So, at this point i suggest sending the barreled action and a few pieces of fired brass to Fred for his "look see".
Bill
I agree Bill. I think as I stated before it will have to go back.
I'm not nearly the expert that some of the others helping you out are, but I have one piece of personal experience to add, based upon your description of difficult extraction and ruined cases. Not sure if it even relates, but maybe.
I had a PAC-NOR 257 Wby barrel built for my 116. I broke it in with about 50 rounds (and frequent cleaning) and then started developing loads. About the 3rd reloading of my brass I began having similar issues: proven mild loads would show serious pressure signs and be very tough to extract. My chronograph also began to read ridiculous speeds, but widely varied.
Long story short, the necks on my brass had grown too long and this was "squeezing" the bullet too tight in the chamber before firing. After ruining several cases, blowing some primers, all the while backing further and further down on powder, I figured it out, trimmed the brass, and everything went back to normal. Could it be that maybe your brass is too long, or the neck in your chamber is too narrow for the brass you are using? This theory is further supported by the fact that you say it's difficult to fit a bullet into a fired case. It sounds like your chamber neck may be so tight that there isn't enough room for the brass to release the bullet properly, hence causing pressure problems, and hence ruined brass and difficult bolt lift and extraction.
Just a thought.
I will not guarantee that is not the problem but I am trimming the brass well on the short side and have measured neck thickness as well as neck size of fired cases and all are in specs.