Light primer strikes or dud primers?

[Geno C.]

I recently bought a custom 358 Win. I necked up some 308 new brass. Easier than ordering new brass since I have this on hand. The problem I am having is I had almost a 1/3 of my reloads were FTF... I assumed that it was because the primers were not stored in an ammo can all summer but now I got to thinking it might be because the cases were not headspacing correctly since it was formed brass. The primer strikes look kind of light but I really couldn't tell you what a strike would look like with the shell not going off pushing the primer back against the bolt with significant force... I was loading off the lands so I wouldn't think that the bullet would have helped to hold it against the bolt.

You think I might be bad primers or light strikes caused by not so solid headspace?

 

[chris112]

Re: Light primer strikes or dud primers?

I would suggest that you load something else with that same batch of primers and see how they work. Ten rounds would probably be enough.

If you just want a guess, mine would be that the formed brass is the problem, ie insufficent headspace.

Hope this helps.

 

[prosise]

Re: Light primer strikes or dud primers?

Pull one of the bullets out, just to be safe. Start putting layers of masking tape on the back of the case, easch layer will add about .003-.004 to the OAL of the case. See how many you can put on before the bolt will not close. It would be nice to remove the extractor plunger if it is a rem 700. This will answer your Headspace question, If you can put several layers on and still close the bolt your right about the OAL of the case being off.
Let us know what you find.

PRosise

 

[Powerlock25]

Re: Light primer strikes or dud primers?

first thing to come to mind would be headspace...

if factory ammo is going bang every time then, I would say you may have your size die turned down too far

 

[ChadTRG42]

Re: Light primer strikes or dud primers?

When you neck up the 308 Win brass, how many stages are you necking them up in? In other words, are you doing it in one step, or using 2-4 neck expanders to neck them up? If you neck up more than about .020" at a time, then you could be pushing back on the shoulder too hard causing this problem. Also, what lube are you using? Some lubes work better than others for necking up. I was forming 338 Federal from 308 Win brass last night, and was using an 8mm (.323") and a .338 die to expand the necks (.015" per sizing). This worked fine. I tried going up in one sizing (.308 to .338), but it requires too much force in doing so. Also, check the shoulder datum point (headspace demensions) on 358 Win vs. 308 Win. They could be different by a few thousandths, which would cause your problem. Also, opening the case up by .050" is a big jump. The brass could be too thin to properly hold a bullet. I'm assuming the rifle, bolt, and firing pin are functioning 100%.

 

[former naval person]

Re: Light primer strikes or dud primers?

Try expanding up to .375, then resizing back to .358 with first sizing with the FL die backed out a turn, then 1/8th of a turn steps back in til the case chambers with a "feel". That will give a false shoulder for the first firing. Won't change the work-up in my experience.

 

[Hummer]

Re: Light primer strikes or dud primers?

Or you could seat the rounds long into the lands which would hold it up to bolt long enough to fireform cases.
I have a 358 I made cases for from 308 brass but I did it different. I loaded 30 cal cast bullets in 308 cases and shot them in the 358 and let it fireform out to fit new chamber. This is much faster and gave me very uniform results with no messed up brass.

You might also call Sinclair and order a L.E. Wilson case gage assuming they make one for 358.

 

[BCP]

Re: Light primer strikes or dud primers?

Probably the way you are forming it.

 

[Geno C.]

Re: Light primer strikes or dud primers?

I do size up in one step. I use regular RCBS case lube. They size up pretty easy I would say. I have some brass that did fire and I am going to load up some of those with the same primers and see if that helps. The ones that did fire shot really well!

 

[Geno C.]

Re: Light primer strikes or dud primers?

I got it figured out I think... I loaded up 10 of the pieces of brass that did fire just with primers from the same box. All of them fired. I then loaded the primers that didn't got off into the same brass and they all fired as well. Headspace is the culprit I figure. I will just have to load the bullets a little longer on the first firing of the formed brass from now on.

 

[ChadTRG42]

Re: Light primer strikes or dud primers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Balthasar</div><div class="ubbcode-body">I got it figured out I think... I loaded up 10 of the pieces of brass that did fire just with primers from the same box. All of them fired. I then loaded the primers that didn't got off into the same brass and they all fired as well. Headspace is the culprit I figure. I will just have to load the bullets a little longer on the first firing of the formed brass from now on. </div></div>
Good to hear!

 

[samnev]

Re: Light primer strikes or dud primers?

If you are getting light strikes I would guess the shoulder needs to be bumprd back. Easiest way to check is to use a Wilson, Dillon etc case length gauge.