Gunsmithing First Brass Inspection after back from Smith

[Prophet78]

Ok, ran a competition this weekend with the gun. I'm seeing accuracy increase. I took a stab in the dark again with a powder charge. I went with 41.7 grains of IMR4064. I had 35 rounds. I did finally get good crony data at the end of the match. I double checked every load against a 55gr Sierra Game King .224 projectile. So, I'm pretty darn certain that I was getting 41.7 grains of powder about every time. Here are my last 9 rounds of the day. Also, I did get a peak at the Sierra manual and IMR4064 max load was 42.6 if memory serves. I missed one somewhere in the 10.

1. 2640
2. 2714
3. 2689
4. 2663
5. 2690
6. 2705
7. 2680
8. 2722
9. 2657
_______
Avg of the 9 2684.

And for the pics of the brass:





I'm still thinking the scratch is something that shouldn't be there. I called my smith and he said not to worry about it. I'm getting a different stock in the next week and if the barrel channel isn't open enough, I'm taking it back to him to open that channel back up. At that time, I'm actually going to write down every damn detail I can from him, to make sure I can dial in the accuracy. My COAL is still at 2.8 or with in .002. I did do a full length size this time around as opposed to the first 17 rounds.

Let me know your thoughts.

-JD-

 

[Lumpy Grits]

74 fps spread is not good. You want 30fps or less over a 10 rnd string.
You also should be ck'n your bullet run-out(T.I.R.). You want .003 or less.
Don't trust a powder measure to meter 4064 with any consistency. Weight ck each charge.
LG

 

[Prophet78]

Lumpy, I'm weighing each charge and double checking it. I'm not dumping any charge unless its double weighed and every 2 or 3 dumps, I'm checking the scale against a known weight.

Can you explain T.I.R. again.

Thanks.

 

[Lumpy Grits]

TIR=Run out of the bullet from the center line(C/L)of the bore.
Bullet has to be centered and 'tru' in the case, to fly straight.
Like I said-Something ain't rite if you have 74 fps E.S. in nine rounds other than low/old batteries in the crono.
I also left remarks to this in your second post--
LG

 

[agbm]

If you are talking about the pin on the primer mark. My primers ALL look like that after being fired. Yes a stock Rem Bolt and firing pin.

-JD-

Normal looking crater for factory remington bolt. I shoot FGMM and my primers crater look just like yours.

 

[agbm]

Here's a few more cases. The Winchester case was from last season, 42.5'ish.





The brass all measure 2.005 to 2.008. Maybe 2.010. I only loaded 25 rounds, I still have 76 that haven't been touched except to debur the inside of the neck.

-JD-

If you look at the primers they all look different, some good and some bad. By chance are you applying a Crimp to you brass? I learned the hard way with a collect neck die, brass looked just like your's. Now I run a redding comp die bushing set and I can control neck tension on all different type brass. No more crimping for me ever again.

 

[nashlaw]

Do what you want, but any one of the pressure signs you have would cause me to start corrective action.

First step would be to back off powder charge. Years ago, I had a Remington .308 that was a hammer with IMR 4064 and 168s. But at 2 full grains under max I had pressure signs, but nothing as severe as what you have.

 

[Lumpy Grits]

Normal looking crater for factory remington bolt. I shoot FGMM and my primers crater look just like yours.

My Remmy bolts don't leave any crater-EVER.
LG

 

[Lumpy Grits]

It also depends on how long he lets the rnd cook in the hot chamber.
Last I will say-back off to 42 gn. Confirm case headspace via a case gauge.
"0" and calibrate your scale--
LG

 

[Prophet78]

I'm going to ignore Nashlaw as he is probably not reading all of the posts in the thread and he is not contributing anything insightful or useful.

Lumpy, I don't want to come off rude, but I said in a previous post I'm at 41.7 grains. I do not have a headspace gauge.

I can't go down to the .01 only .1 grain. Lumpy what kind of shooting are you doing? I'm not a bench rest shooter. I'm looking at getting consistency so I can improve my skill at the range. I don't bench rest shoot at all, and have no desire to.

AGBM did you look at the pic I posted of my latest 35 rounds? All look almost identical with the exception of a few that have extraction marks.

-JD-

 

[Lumpy Grits]

I do see where I added a '0'-SORRY--
Get a Wilson Case Gauge and learn to use it.
4064 is not as temp stable as Varget.
Drop to 40.0gn of 4064, and size your cases the the Wilson gauge.
LG

 

[Prophet78]

I do have a RCBS Precision Mic set.

This:

RCBS Precision Mic 308 Winchester

-JD-

 

[Lumpy Grits]

I trust a case gauge more that those things.
Seen many of them give false readings.
LG

 

[4000fps]

Your hand loads are still not running in the sweet spot. That is way too much difference in FPS.

Your first loads were extremely over pressure. The very first indicator of too much pressure is erratic groups, and erratic differences in FPS between rounds. You blew all the way past that and got the mother load of ejector marks, cratered primers, and blown pockets.

 

[Prophet78]

So, do I continue to decrease my charge to find a spot where the FPS is +/- 30 FPS? Or do I scrap what I've worked on thus far and switch powder and work on an entirely new powder load?

 

[Lumpy Grits]

Drop load-stick with the powder you have.
Use std LR primers.
BUT FIRST--Have your chamber ck'b out as I said in your other thread. You have no leade.
http://www.snipershide.com/shooting/snipers-hide-reloading/255119-advice-my-load-imr4064.html
LG

 

[ridgeway]

I'd also put on your "to do" list, get that firing pin hole bushed by Gre Tan.

Gre'-Tan Rifles

 

[Dogpatch]

I was wondering if the bullet is being seated into the lands. New barrel, is the chamber cutter of a standard design, a hybrid or unknown? Try loading a round then eject the round without firing it. If the bullet contacts the lands, it should show indentations on it.

 

[DAVETOOLEY]

The scratches on the neck can happen with any bolt with a plunger type ejector. When the case neck clears the chamber the ejector pivots the case towards the loading port, right and up. Angle is dependent on extractor type. Depending on case length and the speed at which the bolt is operated the case will hit the upper inside corner of the bolt raceway. Sometimes it's just below the shoulder body junction, sometimes it's the neck. There are several remedies. Reduce the spring pressure on the ejector and/or chamfer and polish the upper corner of the bolt raceway.

This should be a sticky as often as it comes up.

 

[damoncali]

My Remmy bolts don't leave any crater-EVER.
LG

My 700 craters every load I've put through it, none of which have been particularly stout. I've come to the conclusion that cratering alone is not a reliable indicator of pressure. YMMV.

 

[mcfred]

I learn from experience and sometimes having someone put things the way you did. Thank you for the lesson. I'll check the other cases to be sure everything is ok.

-JD-

As a statement of fact alone, nearly all aspects of this topic are covered in the first couple chapters of about every published reloader's manual. Lots of warnings put everywhere in the first few pages about how not to wear your gun on your face. Ignoring them may give you 'experience' that is permanently in your flesh.

So, when playing with explosives it is best to read and understand the proper procedure before learning by experience.

Glad you're ok. Good that you've learned something.

Be safe, have fun.

 

[Greg Langelius *]

Cerrocast the chamber.

Verify chamber length against SAAMI spec. Verify case length against actual chamber length.

Verify neck diameter with bullet seated against actual chamber neck diameter.

Somewhere, expected clearances are likely not present.

Try trimming cases to a shorter length, and turning necks to a lesser thickness; see if this alters the apparent pressure indicators.

Greg

 

[Ledzep]

My 700 craters every load I've put through it, none of which have been particularly stout. I've come to the conclusion that cratering alone is not a reliable indicator of pressure. YMMV.

Mine is the same. It's a .260, and starting loads through near max all are the same "crater". The corners of the primers started to change shape as pressure increased, but the craters stayed the same. I'm convinced it's just a result of a loose fit between firing pin and the bolt face.

 

[agbm]

I'd also put on your "to do" list, get that firing pin hole bushed by Gre Tan.

Gre'-Tan Rifles[/QUOT
I knew there was a fix!!!!

 

[Greg Langelius *]

My load with the 175's, Rem brass, Fed 210M, and IMR-4064 is 42.2gr, and I have always treated it as a max.

I'm far less concerned about primer craters as I am about those ALARMINGLY obvious ejector swipes (gouges, actually). At least one of two things are happening here.

A) that load is TOO HOT! in your rifle.

B) Something abnormal is taking place in that chamber neck area, resulting in severe pressure spikes.

I have seen this before. Shortly afterward, the rifle blew.

Stop what you're doing, verify those chamber neck/chamber length dimensions, and don't fire that rifle again until you are CERTAIN the chamber and neck are sized correctly.

If the Smith used a tight necked match reamer, or failed to ream that chamber and neck to proper length, the net result could end up turning nominal ammo into bombs.

You must take pressure indicators like this seriously.

Greg