Trimming the head of a case, anyone???

[Thor357]

Here's my thoughts/reasoning. If the surface/face of the head isn't perpendicular to the mouth of the case, the case could be off kilter in the chamber just a bit causing a slightly stiff bolt drop.
I have an L. E. Wilson case trimmer and I started facing the case head and mouth and found out that indeed, it does improve chambering/bolt drop. Does/has anyone do/done this?

 

[C.E.Smith043]

I would worry more about the ejector plunger pushing the brass crooked moreso than trying to square the case head

 

[Thor357]

Hmm...I see your point but I'm conducting this experiment with my bolt gutted, no ejector plunger, extractor, springs so in this particular situation the ejector plunger pushing on the case isn't an issue.
I've done about a couple dozen cases this way and I'm seeing some results, not always but some.

Here's more details. The rifle is a Savage Axis II Precision .308. The trimmer is as stated in my opening post. The rifle has about 800 rds through it. I get 1 MOA or better @ 100yds, often 1/2 MOA.
Cases are Lake City. Most have been reloaded quite often, some just once or twice. I have a Forster small base die because using any of my other dies won't re-size the body/head down enough to chamber. I have a T-7 press and Forster seating dies.

 

[over_thetop]

Put an indicator on it and see

 

[Thor357]

Put an indicator on it and see

Umm...I'm not following what you are asking?

 

[PA Jeep]

If your bolt face is true and your chamber straight and you thump the case with 50-60K of pressure how can any misalignment of virgin brass matter after fire forming?

 

[over_thetop]

If your bolt face is true and your chamber straight and you thump the case with 50-60K of pressure how can any misalignment of virgin brass matter after fire forming?

overthinking

 

[Thor357]

Good point!
However, isn't the head of the case the thickest/strongest part of the head? Should it not be affected all that much if any by the pressure generated?
What's happening is after re-sizing, I run into some stiff chambering (no bullet, primer or powder in the case). This hasn't happened before and I have no clue as to what's causing this. It doesn't happen with every case but enough to be concerning. I have a bore scope and the chamber looks fine.
I have seen results from my "experiment" but it doesn't work for all cases. My question is why is this happening?

 

[over_thetop]

Umm...I'm not following what you are asking?

either that or put a square on it and see if it's off a bit if your that concerned about it.

not likely the head is off. Measure the diameter all the way around with calipers. Like three or four points and see.

 

[Thor357]

I have an optical comparator as well as the Hornady gages. They indicate all is square after trimming but I still have a few cases that chamber somewhat stiff.
Does my concern warrant all this fussing around? I doubt it but I'm an odd fellow and stuff like this bugs me. This cr@p hasn't occurred until recently. Rifle still shoots great but...

 

[Mulligan]

Squaring case head with base

https://www.chuckhawks.com/preparing_competition_brass.htm Step 11 indicates some competition shooters are or have been squaring up the case heads with the base of the cases. I am still pondering this one, but thought I would toss it out there and see what is gained from this endeavor. CW

forum.accurateshooter.com

I asked a similar question after reading about it.

CW

 

[over_thetop]

I have an optical comparator as well as the Hornady gages. They indicate all is square after trimming but I still have a few cases that chamber somewhat stiff.
Does my concern warrant all this fussing around? I doubt it but I'm an odd fellow and stuff like this bugs me. This cr@p hasn't occurred until recently. Rifle still shoots great but...

no it's not worth the concern you have. If the case head is uniform all the way around at the web, you're fine.

 

[DocBII]

Good day,

I've done it, usually on new cases. Didn't have much effect on either new or old cases. Other alignment, neck tension, run out, bullet quality and load issues had more effect.

HTH,
DocBII

 

[old codger]

I would check your sizing die and see if you are setting the shoulder back enough. How many times have these cases been fire? All cases do not work harden to the same degree. When sizing cases some may spring back and result in hard chambering. Anneal your cases and resize them. See if they all chamber correctly.

 

[over_thetop]

I would check your sizing die and see if you are setting the shoulder back enough. How many times have these cases been fire? All cases do not work harden to the same degree. When sizing cases some may spring back and result in hard chambering. Anneal your cases and resize them. See if they all chamber correctly.

Ya... anneal, I do. Never considered a problem about case head faces. Shoulder bump and body size chambers freely for me. I've been getting consistent tight groups from controlled neck tension, and OAL with bullet seating.

 

[AccelR8]

I would check your sizing die and see if you are setting the shoulder back enough. How many times have these cases been fire? All cases do not work harden to the same degree. When sizing cases some may spring back and result in hard chambering. Anneal your cases and resize them. See if they all chamber correctly.

I had a problem bolt handle requiring a bit of pressure to close on fired and resized cases, when new cases or fired/not resized cases did not have this problem. Turned out to be a mismatch between my die and chamber. Resizing actually moved the shoulder of a fired case forward (ever so slightly) rather than pushing it back.

 

[J.d. Popkes]

This is not a thing. Get good components and prep them correctly. Even with a savage factory rifle.

In my humble opinion….

 

[Fast14riot]

German had an article about this, mostly due to long cases like '06 based that can come out of the sizing die banana shaped and he would mark case heads to be able to chamber them indexed the same way.

 

[dellet]

There is a few things I would do before trimming case heads. First would be figure out why you need a small base die shooting a bolt action.

The T7 is a great press, but not for forming brass. There is a difference between resizing and forming. If you are using a small base die, it’s closer to forming pressure needed. The turret will tip.

If you are not using Redding competition shell holders, you’re probably not getting the die to have full contact with the shell holder. This can be another issue with the T7 when it tilts. If you size the brass twice and turn it 180 for the second size, it might correct itself.

If the bolt won’t close on sized brass, are you certain it’s not the base diameter? Even a small base die does not size below the 200 line.

Finally, if the case head is not square to the body, it will likely show up one of two simple ways. If the case mouth is square to the body after trimming, simply measuring with a caliper and holding it to the light, you should be able to see light below the case head on the caliper surface or anvil on one end ore the other. Same check at the shoulder. Might indicate which end is not perpendicular tonthe body.

What it really sounds like is brass that was fired in another chamber, possibly an auto loader. If that’s the case, then it’s better just to get new brass.

 

[ronemus]

If you have a few firings with stiff loads, it's likely that the base of the case has expanded below the point where the sizing die can reach. I've begun using Lee dies intended for lead bullet sizing as push-through dies for my brass; Lee will make them in custom diameters for a very reasonable price. They also help prevent enlarged primer pockets.