This is a discussion on Warning -- Blown Up Kahr CW 40 (should read if you relaod) within the Reloading forums, part of the Defensive Ammunition & Ballistics category; I'm putting this here as a warning to not only new reloaders but us old timers as well. When you start reloading, the first thing ...
I'm putting this here as a warning to not only new reloaders but us old timers as well. When you start reloading, the first thing you should buy before you get a press, dies or anything else is every reloading manual you can afford. And once you start reloading, compare loads from several different sources BEFORE you decide what charge to start with. And it's just my opinion, but I think it's valid, when there is ANY doubt, default to the data supplied by the powder manufacturer. I feel that they have probably done the most extensive testing with their own powders and have produced the most trustworthy data.
Now, the reason for this post. Just got off the phone with my old shooting buddy who blew up his new Kahr CW 40 today using a published load. This came about mainly because, even though he's been loading for 40+ years and knows better, he used a load without checking it against several other sources. He took a load from the Sierra #5 reloading manual for a 165 gr. Sierra JHP bullet using Hodgdon Clays powder. The Sierra manual (I have mine right in front of me) lists a starting load of 3.4 grains of Clays with a maximum of 5.7 grains of Clays. They list an "accuracy" load of 5.2 grains of Clays, which is the charge my friend was using. Case completely separated at the rim, blew the side plate off the gun and blew the magazine out the bottom. It was the last round in the gun, so luckily no more rounds in the magazine that might have been detonated. When he called me, I looked up the load data on Hodgdon's web site and found that for the exact same bullet, a 165 gr. Sierra JHP, their loads were a starting load of 3.5 grains of Clays with a maximum charge of 3.9 grains of Clays. This means that the 5.2 gr. accuracy charge from the Sierra manual is 33% higher than Hodgdon's maximum charge and Sierra's maximum charge of 5.7 gr. is 46% higher than Hodgdon's maximum charge. Result -- blown up Kahr. I have no doubt that Sierra's data is accurate for the gun they tested it in -- a 5" barrel Para-Ordinance P-16, but different guns produce different results and that's why you have to compare sources before deciding on a starting load.
Reloading can be a safe, fascinating and money saving hobby but it can also be dangerous. Always, ALWAYS, double check your data. And for Heaven's sake, don't use somebody's pet load you found on the internet. In this case, my buddy was using published loads from a reputable source but by not following one of the most basic rules of reloading, he now has a blown up gun. Luckily, he was not injured but he could have been very easily.
Be safe -- Play safe.
Last edited by cvhoss; March 17th, 2008 at 11:37 AM.
Thank god he wasn't hurt,I have 3 load guides i use,and i always start on the low end,even tho i don't have a chrono yet as long as my loads recoil less than factory and i load under max i feel i'm good,and i load fun shooting plinking loads not heavy loads.
5.2 gr's of clays sounds like a typo error ? , 3.5 of clays sounds right for a maximum , due to past experince i start 10 % below the start charge and work my way up till i reach my max charge , which is usually less than the listed max charge , there is bad load data out there , thats why it all says " use at your own risk " i am glad he was not hurt , when in doubt i contact the powder mfg they have all been more than happy to help me sort it out .....
The Hodgon's site lists for a Sierra 165 JHP the initial charge at 3.5 grains and the max at 3.9 which will develop pressures from 29,900 PSI to 33,300 PSI. Going by cvhoss' percentages (and I might be very wrong in my thought) the gun might have sustained around 48,000 PSI worth of pressure. And to bring it to regular terms, +P ammunition is usually 10% above max load or 36,000 PSI!
You have to make the shot when fire is smoking, people are screaming, dogs are barking, kids are crying and sirens are coming.
Ego will kill you. Leave it at home.
3.4 / 3.9 (already above Hodgdon's max) / 4.3 / 4.8 / 5.2
Correction to original post!!!
Here comes the human error part. While typing my original post and looking at the Sierra manual, my eyes crossed lines in their book. Their maximum listed charge is the 5.2 grain "accuracy" charge. The 5.7 was from the line above in the book and did not apply to Clays. My fault. None of the 5.7 gr charge information in the original post is applicable, but the 5.2 gr charge is. Sorry for the mis-information.
I have blown up a Glock 40 due to reloading the brass one to many times. I was using Accurate Arms Powder. There was a Shot Show in town right after that and I found the Accurate Arms booth. There were telling me that the 40 cal. was the most volatile round to reload there was. Shortly after this they removed the 40 reloading data from their books. This was several years ago and I haven't look into it since than. Be careful.
Blessed be the Lord my strength, which teacheth my hands to war, and my fingers to fight.
Senior Instructor for Tactical and Defensive of Texas
well there are also warnings all over the place that glocks and some other 40's and 45's chamber's do not fully support the round [ completly enclose it ] that the chambers are open at the bottom , i would bet this is the case with the Kahr ? and they say you are to stay away from the hot loads and only use the brass two or three times , so check your gun and reload auto's carefully , and talk to the mfg if in doubt , cause in the long run if this is the case ,it is just cheaper and safer using cci blazer for practice , than blowing up a $600 glock or a $ 700 Kahr .......
No firearm completely supports the case.
07/02 FFL/SOT since 2006
Probably the only home based FFL that doesn't do transfers.