welding a bolt /cocking . long question .sorry

[jerryatric]

hi , i had a omark action fitted with new adaptor & 30 barrel about 12 months ago /6.5 x 47 lapua / no problems untill now . i have been full sizing the same 50 lapua cases - & put around 500 rounds through the rifle using these cases . MY PROBLEM is ,recently after firing it is very hard to lift / pull the bolt back - i have to give it a good thump with me hand , & no im not anywhere near over loading the cases to max . NOW FOR THE STRANGE PART - when i dry fire the same cases using my 308 bolt from my other omark the bolt lifts easy ? . rifle was put together by well know gun smith on the coast of QLD . could it be the cocking sear part on my bolt . apparently they wear & i was told to run a weld to build it back up - i have been welding for years on old cars ect so can i do this myself .i have another bolt to copy from so can not see the problem . & yes when i look at both bolts i can defintly see the wear differences . gun is accurate & im only using about 36.5 grains of re-15 . does the same thing with 2209 // 2208 .

[bruce moulds]

jerryatric,
have you full length sized that brass?
bruce moulds.

[johnk]

First, it's entirely possible to get different headspace with different Omark bolts - they were made with interchangeable bolt heads for that purpose - but in any case, bolt heads with the same number may give a different outcome because of wear over time.

Secondly, Omark bolt handles are brazed on, so welding up the camming corner risks the potential of the handle detaching. I would recommend against that. If adjusting is necessary, it would be better to biuld up the angle on the action body & dress it back, but exhaust every other possibility first.

Third, if cases would previously load & extract fine with your moderate loads but don't now, then it's more likely, as Bruce said, to be a case conditioning issue:

Perhaps they've changed physical properties over time such that there isn't enough springback to free them in the chamber after firing.

Maybe your prep process has deformed the critical body dimensions or your process has been altered slightly in recent times.

Maybe you have a buildup of something in the chamber that's reducing the dimension somewhat. Back in the days of reloading military brass, Omarks were notorious for getting a "meniscus" of crud left in the shoulder/body junction of the chanber. Spinning a .45 bronze brush on a rod in the chamber followed by a wipe out with a close fitting solvent coated patch usually resolved that.

Can the cases be rechambered again after firing & before you prep them again?

[Malcolm Hill]

Hi jerryatric
If the cocking cam on the bolt body is the problem then the bolt handle will be hard/ sticky/ rough to lift if it has been dry fired in the rifle with no case in the chamber. Make sure the cam is greased as well as the thread in the bolt body(and also the locking lugs on the bolt head) as this also has an influence on the force required to lift and cock a fired bolt. If it works ok without a case in the chamber then the cocking cam is not your problem. If the bolt is hard to lift only after firing a round there are several issues that can be involved. Due to manufacturing tolerances, wear and changes to action / bolt relationships when fitting the adaptor the timing and clearances on the extractor cam can become less than ideal. If cases get a little dirty or have been fired many times and become a tight fit in the chamber they can get difficult to remove if everything is not set up right to give good primary extraction when lifting the bolt handle. Even little things like too much clearance between the extractor claw and the bolt face can cause all the extractor cam to be used up before the case is pulled back out of the chamber requiring that the bolt handle then needs to be tapped back to actually free the case from the chamber. It sounds like you probably have a combination of a few of these issues causing your problem and well used cases compound the problem. If you get it looked at by someone familiar with these Omark problems it can be fixed to give good extraction if set up properly.
Regards Malcolm

[jerryatric]

hi .thanks everyone who has commented so far , i have just double cleaned chamber - still no gunk or anything has come out - so its defintly clean , YES i full length size all cases after every fire as i have no neck size die .only full sizer ect , ALSO the bolt head on the 6.5 is stamped with number 4 & its hard to lift after even a dry fire ,WAS EVEN A BIT LIKE THAT WHEN IT USED TO BE A 308 before i rebarreled it // BUT my 308 bolt head is stamped number [ 1 ] & when used with same case & dry fired is dead easy to lift . any thoughts on this ? . also the cocking sear part is worn down to me as i can see a difference in least 1 to 2 mm - & its the worn one thats hard to lift after dry fire ect , please keep the comments up people as its defintly weaving the problem down !. i know this may sound a bit confusing the way im putting it across but its the only way i can describe it - sorry . AGAIN THANKS EVERYONE .

[ratshot]

Dont stuff around with it if it worn out replace it Omark parts are cheap the Q store at the QRA should have the bits

[johnk]

If a fired case are stiff in a clean chamber, it does seem like your cases have qualified for retirement because they now fail to spring back after firing due to work hardening or loss of elasticity.

One possibility is that your sizing die isn't doing the job it once did, either because it has got out of adjustment or, for example, that you are using a different sizing lube than you did in the past. The fact that you don't have chambering issues with a bolt head that is several sizes looser (I forget what that means in thousanths of an inch for Omarks) suggests that you aren't pushing the shoulder back enough (any more).

Alternatively, you may have had your die set up to size more than was necessary, which in itself generates headspace prior to firing and riviting of the case head & stretching of the case each firing. The ultimate outcome of this can be case separation.

Your die should be set up so that the case j-u-s-t enters the chamber with barely preceptable force on the bolt handle. If you have to force it, it's not sized enough; if the handle virtually drops down, then you've gone too far.

Don't confuse yourself with what might have happened with another chambering. For all we know, you might have generated a similar problem for the same reason you have the problem now.

[jerryatric]

hi , thanks john , as a matter of interest i have allways thought the die was not set proper , its one of thoses forster comp die sets & has allways had me stumped from the start - yep that proberly makes me a dumb a#s. i even managed to crush 4 cases while attempting to set the full sizer up . it doesnt matter how i set it -it never seems right . & maybe the 50 cases have lost thier spring ect . maybe its not the rifle / maybe its my loading setup ?.

[Barry Davies]

jerryatric.
Consider the 308 Win.
When a barrel is fitted your gunsmith will set the headspace between the limits of 1.630" ( Go ) and 1.634" ( No Go )
Personally we set ours at 1.630"
Head space gauges are available to measure this.
A fired case from a rifle set at 1.630" will usually come out and measure 1.630" /1.631" varies with the case.
When you size your fired case it should measure the same. ie you adjust your sizing die to give the same reading.
However to do this you need a gauge that you can measure the fired or sized case with.
With such a gauge you can minutely adjust your seating die to give say 1.630/1.6295 or whatever.
Without such a gauge you are just guessing. If you are neck sizing only then all should be ok , but a gauge will tell you if you have done something incorrectly in setting up your die, it takes one of the " maybe's " out of the equation.
What John says is absolutely correct but without a gauge it's all a guess.
Barry

[jerryatric]

hi, i have been on the forster web page & followed thier instructions in setting up thier dies , i have re-adjusted my dies & now the stiff cases chamber easy -also i can dry fire & lift the bolt easy . maybe i have fixed the problem - i wont really know till i fire one off & try to extract the case .... though i must say it takes a lot of force on my press to do this . i use one of those real big - blue - simplex presses which are very strong.
thanks [ b-davies ] as well for your input , with any luck i can finaly sort this rig out . as its just too dam accurate to give up on .

[jerryatric]

well just got back from testing . i have re-adjusted the F / L / DIE . when dry fired the bolt now lifts easy compared to before , using the same cases . i tested 3 cases - results are 2 cases lifted / extracted easy & only 1 case was still hard to extract , im really starting to think the cases are stuffed & have lost thier spring .
like i stated earlier in this topic i have had around 800 + shots through this rig using the same 50 cases which have been full length sized after each firing . so that adds up to a few reloading in each case .
just wondering if i should risk trying the other 50 cases i have & maybe buying a neck sizer die instead ?. thanks for the help so far people .

[Barry Davies]

jerryatric.
Good test for cases is to try and rechamber a fired case. If it won't chamber easily good chance cases have had the gong.
FL sizing every time you fire will dramatically reduce the life of cases and work harden them much quicker.
Suggest a neck sizer only, in conjunction with a Body Die ( Redding ) This combination will add life to your cases plus you will find that when they do eventually fail it will be by necks splitting and not the dreaded case separation.
Barry