Primers
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Category: Auto Mag Pistol
Forum Name: Message Board
Forum Description: Message Board
URL: http://www.amtguns.info/forum_posts.asp?TID=1007
Printed Date: 27 Mar 2026 at 1:11am
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Topic: Primers
Posted By: Gaylon
Subject: Primers
Date Posted: 07 Apr 2012 at 8:04pm
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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. Thanks Gaylon
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Replies:
Posted By: Auto Mag
Date Posted: 07 Apr 2012 at 8:58pm
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Too much powder, wrong primer, firing pin problems, there are a whole bunch of reasons why this might happen. Be careful, you cold be on the edge of breaking something. What primers are you using ? What specs are you sizing and loading your brass to ? Can you provide any details about the gun ??? And pictures of your fired brass (from several angles) would help.  |
Posted By: curmudgeon
Date Posted: 07 Apr 2012 at 10:21pm
| 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??? |
Posted By: omie01
Date Posted: 07 Apr 2012 at 10:41pm
All of the above! Sounds like it's time to do some investigating! I know that that can really wreak havoc on a gun. A buddy of mine had that happen with his .500 Magnum and it burnt out the firing pin retainer!
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Posted By: Auto Mag Whisperer
Date Posted: 07 Apr 2012 at 11:13pm
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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 |
Posted By: Auto Mag
Date Posted: 08 Apr 2012 at 3:22am
| Good advise to be sure!!! |
Posted By: Gaylon
Date Posted: 09 Apr 2012 at 8:26pm
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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 Gaylon PS. I don't think I am showing off, I don't go to a public range I have my own. I just like to load and shoot different kinds od guns.
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Posted By: curmudgeon
Date Posted: 10 Apr 2012 at 12:36am
| .010 is too much headspace in fact .008" is too much. FWIW dept. |
Posted By: Gaylon
Date Posted: 10 Apr 2012 at 1:35am
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Thanks I will leave it at .005" Gaylon
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Posted By: Rumore
Date Posted: 10 Apr 2012 at 3:24pm
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I don't know about the 44 AMP, but the .223 no-go is at .004" and the field gauge is at .006". So when you're chambering a barrel, it needs to be .001 - .003. If the field gauge closes, you're over .006" and the barrel is headed to the scrap heap. (or set back and rechambered) Tony |
Posted By: MAX GERA
Date Posted: 10 Apr 2012 at 11:47pm
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That is the range that I use. I made my GO gage 1.300. that's .002 above nominal case length of 1.298 and the NO GO 1.304. Industry standard for case length is nominal length +.000 -.002. That will give less than .008 maximum head-space on a maximum chamber with a minimum shell. However, looking a the prints for the Auto Mag, by adding all of the dimensions of the receiver, barrel and bolt, we find that they add up to a chamber length of 1.306 to 1.310 giving us up to .014 head-space with a maximum chamber with a minimum shell. Way too much for my taste, and that is assuming that the gun is within tolerances (Do you feel lucky?). This does not take into account that apparently much of the available commercial brass is way under the industry standard. My last batch of Star Line was running about .010 under nominal. The results of such head-space were clearly shown by Luc's pictures of case head separation a few posts back. ------------- To get things done, stop talking... Start doing! |
Posted By: Gaylon
Date Posted: 11 Apr 2012 at 3:52pm
| So, Should I leave the head space at .005" |