Gunsmithing Irregular Case Mouths

[nashlaw]

I am having irregular case mouth dents on fired cases in a bolt gun. I am being very careful when I remove the fired cases and make sure they do not hit the ground and get dented. Accuracy is very poor. The dents on the mouth of cases are flat spots that are very noticeable and the mouth is out-of-round.

Do you guys have any ideas?

david

 

[Hateca]

Re: Irregular Case Mouths

Just because it's not hitting the ground doesn’t mean it's not getting flattened leaving the chamber. Simply clearing the chamber the case will smack the inside of the action before it leaves the rifle and this can also dent the case.

Help the round from the chamber by holding pressure on the case as you pull the bolt to the rear keeping the ejector from pushing the case into the action then inspect the case and see what you have.

 

[jayjaytuner]

Re: Irregular Case Mouths

im actually having the same problem with my new surgeon.

flat spot on the case mouth and irregular, not round...... kinda oval;ish
accuracy is not poor, but case is takin a smack on the way out.

is this a Norm?? or somthing to worry about...

maybe they're smackin somewhere on the inside of the action i'll have to check neck time i shoot er.

 

[wnroscoe]

Re: Irregular Case Mouths

The ejector spring is too strong. As soon as the case leaves the chamber it's hitting the side of the receiver. I cut three coils off of my ejector springs and it seems to help.

 

[Al Nyhus]

Re: Irregular Case Mouths

Yep..the ejector spring 'loads' the case by levering against the case head. When the neck clears the rear of the chamber, it gets smacked into the side of the action as it continues it's way rearward with the bolt....this 'smack' is what dents the case neck at the mouth.

Clipping a couple of coils off or substituting a weaker spring will take care of it. On my 700's, I have each one set up so the case will just 'roll' out the side.

P.S. On a gun with a loose or factory chamber, removing the ejector spring can sometimes cause a nice increase in accuracy...especially if you're f.l. sizing. The ejector can load a sloppy fitting case to the side and the bullet enters the rifling not well centered to the bore.

 

[jayjaytuner]

Re: Irregular Case Mouths

can someone explain how you go about removing the extractor spring so i can shorten it a little...

can i do it with a sinclair ejector compressor

then is there a pin to punch out?? what size punch is reccomended...

help much apreciated!!

 

[GasLight]

Re: Irregular Case Mouths

I am not 100% sure the ejector compressor is necessary, but it may help you from losing the ejector when you knock the roll pin out. The pin you need to remove is a roll pin, I have had luck carefully pushing one out with a regular punch, but they do make roll-pin punches that work much better. I don't recall the size exactly, but if you use a standard style punch, make sure to clean it well first, and then use a punch that is just under the size of the hole. Take is slow or you can bend the lips of the roll pin, this is more vital on the way back in though, as it can widen the pin and make it impossible to seat it all the way back in. Here is a pic of the pin you need to punch out:

HTH
DD

 

[jayjaytuner]

Re: Irregular Case Mouths

thanks for the help,! aprecite it

 

[jayjaytuner]

Re: Irregular Case Mouths

got er, cut about 3 links off the spring & replaced it, hopfully this takes care of the problem.

 

[Victor N TN]

Re: Irregular Case Mouths

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wnroscoe</div><div class="ubbcode-body">The ejector spring is too strong. As soon as the case leaves the chamber it's hitting the side of the receiver. I cut three coils off of my ejector springs and it seems to help. </div></div>

I've seen this before also. Watch when you pull the bolt back and see if hits the receiver.

 

[nwilling]

Very old thread coming back from the dead but I have the same problem. Have people been solving this by cutting the ejector spring or just letting the spring break in? I have to guide each piece of brass out with both hands while cycling the bolt and with 80 rounds through the action now this is getting to be annoying.

 

[nwilling]

Anyone?


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