...Blew primer out of case...

TargetNorth

TargetNorth

Regular
Rating - 100%
23   0   0
Location
Southern Alberta
Hi Guys
I was shooting some .243 Win today,
37.8gr Varget
65gr Hornady VMax
3660 fps

I had one that sounded different after shooting, opened the chamber and voila, no primer. It was sitting in the magazine. There was soot marks on the brass and a bright spot indicating primer flow.

I am at the lowest load in my Lee manual, but speed is almost at the top of the highest. Primers are slightly flattened, but I'm using Federal (supposed to be soft?)

Kinda made me nervous, as I've shot this load before. I kinda wonder if my scale is accurate...

This is an indication of unsafe pressures right?

The brass was loaded 5 or 6 times...

Thoughts? Anyone have this happen to them?

Thanks,
Barry
 
Did you have any cases that the primer felt kind of loose when you primed them? Do you look in the neck of a case and ensure that each case has a similar amount of powder? Are you using the same brand of cases as mentioned in the loading manual? I have seen differences of a few grains in case capacity from one brand to another. It is a safe bet that if you were approaching max velocity for a cartridge, you were approaching max pressure. Are your cases stretched? If they are too long they do funny things. The 243 is a high pressure cartridge, and there is not a lot of room above normal operating pressure. Was this one load an individual, or are all of your primer pockets stretched now?.....I did send a scale back once to get it calibrated, so your scale could be out. To check it weigh a bullet, then weigh two, then three. They should be exactly as many grains as advertised.
 
Primers all felt OK when priming them.
I check all cases with a flashlight to see if they are approx same amount of powder. I also weigh each charge individually. I throw to about 90% then trickle in the rest.
I don't use the same case as the manual, I'll check out that!!!
I trim the cases every couple of reloads.
I'll check the scale against a bullet to see how close it is.

Thanks for the ideas,
Barry
 
Well - If your chrony is correct, then you are at the hot end of the spectrum, and what you experienced is likely a combination of loose primer and overpressure.
 
Simple equation Velocity=Pressure. All things remaining equal (powder lot, primer, bullet and case), you cannot get more velocity without more pressure, unless you use a longer barrel.

If you are using the same length or shorter barrel as the manual that produced the load info, then you are at the same pressure as they were when your velocity equals theirs The combination of changes in components and difference in your chamber, results in higher pressures at a lower powder charge. Not a bad thing, but it is why it is important the Chronograph your loads if you can. This is the best indicator of pressure, short of having a strain gauge available. All of the other indicators, flattened/cratered primers, stiff bolt lift, shinny spots on the head of the brass etc. where all developed for times when most people didn't have access to chrongraphs. At a cost of $100, this should be part of every reloaders equipment, to ensure safe loading and to truly understand what changes in components, OAL and the like are doing to your loads.

Side note - For every inch your barrel is longer, in most calibers and depending on burn rate of the powder, you can probably get 50-75 more fps, at the same pressure
 
What manufacturer of brass was it ?? I came back from range with my cases, put them in tumbler. When I took them out I realized that about 10 were missing the primers. They were all Federal with 223 head stamp. Needless to say I sorted my other brass and got rid of all Federal with 223 stamp. The federal with just date code seems to be ok.
 
37.8 gr of Varget is below minimum. Only .2 grains though. Hodgdon gives 38.0 as the starting load, at 3494 fps. The data on their site just happens to use 65 grain V-Max bullets.
If you have any left, pull a few and check the powder charge.
Most likely tired cases.
"...supposed to be soft?..." Federal brass is known for being softer than other brands.
 
I agree Chronographing loads is essential, and according to velocities on my chrono I was close to but not over the top speed.

I am using Federal Brass. I found 38 gr Var to be the perfect load for this rifle with other brass (Win I believe) and since I switched to Federal, I downed the load .2 to the minimum in one of my reloading manuals. Looks like it's right up at the top still!

I'm going to toss this bit of brass (50 of them) and start with new stuff, it's been all shot at least 5 times and... everyone likes new things right? :)

Thanks for all the replies,

Barry
 
You must log in or register to reply here.
Back
Top Bottom