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Monday, 29 May 2017

Over Cautious Pistol Loading Data?

I've just read how one very honest shooter wrote his story about blowing-up his fine bolt-action rifle (in Gun Digest 2010)   .. He carelessly loaded some rifle cartridges with pistol powder and very nearly killed himself in the explosive demolition of an excellent hunting rifle.

- You really have to stay alert and careful when working with firearms .. and when hand-loading ammunition. Check and double-check. 

I found some loaded "dud squib-loads" recently (again) and when I checked the Lee powder charger disc in the press ... it had spider webbing partially blocking the charger feed bore.. I guess that it had been invaded by a wee jumping spider in the weeks since I had previously used the press with this set-up.
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I have an interesting situation with my loads for my 327 Federal Magnum.  I have some .32" S&W "Long" brass that I'm using for lighter target shooting and 'plinking' recreational shooting.

- This is much like using 38 Specials in a 357 Magnum revolver.

I loaded these 32 S&Ws  with 2.6gns of AP70N powder behind Hornady 90gn lead semi-wadcutter pills. The ADI Handloaders Guide lists 2.7gns as a Maximum Load.

- So I used only one tenth of one grain less than the suggested MAXIMUM safe load.

They shoot very nicely and accurately .. no recoil to speak of - BUT ... It's too light a load. The powder charge has enough energy to push the bullet down range and through a paper target - but not enough strength to OBTURATE the Lapua brass cases - and expand the case to seal the chambers against the propellant gasses.
Look at the state of them - This is new brass only fired the one time.

The remedy will be to increase the powder charge by a wee bit - but how much - bearing in mind that I will then be theoretically exceeding the Maximum Load listed there for the .32 S&W Long?

- I'm going to try about half a grain more of the same AP70N powder in a few rounds - going to a charge of say 3.1 grains or even 3.2 grains and I'll have to 'read' the cases and primers for pressure signs such as primer flattening. - There should be no risk of over-stressing the Ruger revolver as it is designed to work with the SAAMI maximum pressure level of 45,000 psi of the 327 Federal Magnum.

I do understand that the US is a very litigious country - and if I was publishing loading data I too would be very careful .. but there is a risk here that the starter loads may be so weak as to cause barrel blockages and possible blow-ups that way.

Commercial ammunition sellers are very cautious with calibers that have been around for hundreds of years (.32"Short" since 1878 - "Long" since 1896!) - as they might be used in unsafe very old guns .. but surely that would be the gun owners problem?

This over-cautious light loading of 'Thirty-Twos' may go a long way to explain their shooting magazine reputation as being 'pip-squeeks'.

Marty K.