Potential Problem

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  • Last Post 13 April 2010
madsenshooter posted this 03 October 2009

I wanted to get some opinions on something I'm experiencing with a load in my Krag.  The load is 20grs of Blue Dot, Rem 9 1/2M primer. 169gr bullet, the Eagan MX3-30AR, or rather a clone thereof.  I'm estimating pressure in the 35,000 PSI range.  But take a look at the case.  It appears the Blue Dot is being blown to the front before it begins to burn.  This pressure mark, which is on all the cases fired with this load, coincides with the forward edge of the receiver ring too.  Am I taking a chance on ringing the chamber with this load?  Does anyone else see a pressure area like this on their reduced loads?  There has to be some other powders that get blown forward before ignition, 2400 ought to be a candidate.  Ed, you're a Krag shooter, ever seen anything like this?

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offhand35 posted this 03 October 2009

Some other questions to ask are: How do the primers look compared to loads that are known to be ok? Any chance that you can measure/compare the diameters of the cases just above the rim from unfired, fired factory, fired known ok loads, and this load? How about effort required to open the bolt after firing? Is it greater than that for a known ok load? The same comparison should be made in regard to amount of effort needed to extract the fired case. I seem to recall some references in Handloader Magazine to the extreme high pressure effects found in loads that fill a case at less than a certain level <% of total capacity>. To what level does this load with Blue Dot fill the Krag case? I will have to dig around from issue to issue for those references, unless someone here can point to a specific source.

The marking you are seeing on the case may or may not be indicating excessive pressure. You should look for other signs to confirm the consition. O/W you may simply be observing that this load expands the case completely in the chamber where others do not.

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RicinYakima posted this 03 October 2009

My take is that you have a swelled chamber in front of the receiver. Krag barrels are soft and this has happen more than one over the last 120 years. Ric

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roadie posted this 03 October 2009

I think it's swollen too, if not, there is some kind of damage at that point in the chamber.

roadie

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madsenshooter posted this 04 October 2009

Primers are well rounded at the edges, no swell to the case, a good straight edge layed on it doesn't show any, extraction is normal. Quickload says the load should generate around 35,000PSI. Best I can measure 20grs fills to 1.25” back from the mouth, so 2.3-1.25=1.05 forward of the base. Filled to the mouth the case would hold 42.1gr, so I'm a bit below 50% of capacity. If the barrels are soft, perhaps it's just the barrel gives at 35,000psi where it isn't surrounded by the receiver ring. I dunno, don't have the answer, just know I don't want to ring it. Appreciate the input gentlemen.

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madsenshooter posted this 04 October 2009

Ric, Roadie, I'm unhappy to report that it appears you guys are right. There is very slight bulge at the pressure line. Got the straight edge in better light. With the taper it doesn't effect extraction. I don't think it was the Blue Dot load at all. I was messing around with WC860 one day under a 200gr bullet. I shot one of the load and it kicked the snot outta me, so that was enough. When I started to reload that case the primer pocket was expanded, so it was a warm one. Luckily, I've hoarded away a couple more full length barrels, and there's the possibility, I understand from following the Ask Orest post on the CMP Forum, that they may have some newly manufactured Krag barrels available! Any of you other Krag shooters with worn or stupidly damaged barrels, post there, if there's a demand, they'll probably do it! Thanks guys!

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madsenshooter posted this 06 October 2009

Well guys, I had a new old chamber reamer, and ran it in the chamber, before cutting any metal, it was removing quite a bit of carbon, could be the fellow that had it before me was a cast shooter too. Plinking loads that don't seal the case can leave quite a mess of lube and powder residue in chamber. The reaming increased the diameter the neck and body by .0015-.002 and subsequent test firing with a new case and load of 4227 says things are ok. The reamer didn't change the throat, looks like it was cut for spire points. Got a new 311284 from a group buy on Castboolits, giving it a workout right now.

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JetMech posted this 08 October 2009

Just a suggestion. At this point, it might be smart to make a chamber cast to ensure you haven't exceeded SAAMI specs and determine the true dimensions of your chamber.

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Ed Harris posted this 15 October 2009

Not sure I trust QuikLoad on Blue Dot as Alliant has had problems with lot-to-lot variation, so I don't use the stuff at all. I don't shoot more than 20 grs. of #2400 in a Krag for a heavy load and 15 grs. for a target load with #314299.

With 200-gr. GC or 180 jacketed bullet max. load is 30 grs. of RL-7 or 28 of 4198, about 1950 fps.   Also good for full load is 38 grs. of RL-15 with 180 jacketed, about 2200.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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madsenshooter posted this 10 April 2010

Hi Ed, been awhile since I posted the above. I have to use it. If you could see what that load does with the Eagan MX3-30AR, you'd want to shoot it too! It should do about the same with your Lee 155. Got a friend who recently decided to use up some his BD after reading some of my posts on other forums. I received an email from him, subject: BD Kicks A--! He'd been using 2400 before with lackluster results, despite having a new CMP barrel. I still think the magnum primer blows the little flakes to the front of the case before it really starts to ignite, but that contributes to the consistency, went to my local range last week to find out just how fast it was going, of course the chrono was down. Maybe this week. I know from shooting the Eagan in my K31 that my alloy is good for 2450fps, so as long as it don't blow up, and I've shot several hundred of them now, it don't matter how fast it's going really.

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JSH posted this 12 April 2010

In my experience, BD is about as position sensitive as I have ever fooled with. I have followed a few threads on BD and my gut tells me to stay away from it. jeff

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madsenshooter posted this 13 April 2010

Ever try it with magnum primers? Doesn't seem to be position sensitive to me, I load haphazardly, put the bullet point down as I load it into my Krag, or point it up then drop it in on the level, it doesn't seem to care. I've read different things from different folks, but it works wonderfully for me. That's good as I have about 5lbs to use up. The mark in my post above had naught to do with pressure by the way, it was lube flow from firing low pressure loads, not readily visible until I started firing loads that sealed the case.

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