Primers

Could anyboby tell me why I am blowing holes in the primers? I am loading 357 with 140 gr. Hornady XTP bullets with 26.5 grs. of H110. I got this load from a old Handloaders mag. dated 1975. I am using both 308 military and starline brass.

Have yo taken your firing pin out and checked for original lube congealed around the FP spring, allowing the pin to stay forward a fraction to long. I have experienced this in a Luger allowing t to be a fixed pin bolt and running a full mag full auto. Have seen it in an AM, plus a host of other reasons. Should not be too hot a load in Starline brass. Examine the tip of FP under magnification for a small tit. How manyn times has this happened???

 

I can think of several reasons for a pierced primer.   One of them might be: 

POOR SEATING

In the case of the 44AMP, if you have a long case or a short chamber, the worst thing that happens is that the Auto Mag will not go into battery.

In the 44AMP if you have a short case or a long chamber or both,  you can still chamber and fire the Auto Mag. 

The case going too far forward can cause it to seat on the rear of the extractor.  This means that the case is not touching the bolt-face, which is bad.  The firing pin hits the primer, which farther pushes the case forward and up against the rear of the extractor before ignition.  With the case in this position, the loaded round now ignites and recoils rearward into the bolt-face.  If you don’t puncture the primer, you will usually see the imprint of the ejector on the spent brass.  One can easily in-vision this scenario and understand that the primer is now pushing the firing pin rearward before the firing pin spring can pull it back.  This can cause a primer piercing.  Even light loads or factory loads are susceptible to this malady.  Extractors can sometimes break as a consequence of poor seating.   

The shoulder of the 357AMP just adds another variable to the situation. 

Pierced primers mean less than nothing to a casual shooter who just wants to show off the Auto Mag and make noise.

A serious shooter will perform the GO NO/GO routine to determine what his, or her chamber length is to properly load ammunition for a particular Auto Mag.  Same goes for the 357AMP.

My Opinion…………I have seen this situation more than once.

Bruce Stark

I think I took care of my problem. I checked head space and closed it in to .005" and after checking all my notes on all the different loads I have used for the 357, I dropped the charge back 23grs. (H110) It shoots and cycles nice. I think I will open up the head space to .008" to .010" unless some body thinks that might be a problem.  Thank for the help

Thanks