CCI #41 to 450 in 300 BO

Nathan

New member
Wow! I loading Hornady 110 VMAX with ~17.9 gr Ramshot Enforcer under them. I was developing a load with 41's but the best groups were ~1.5" at 50 yds. Most were 2"....With 450's, I'm solidly under 1" at 2 charge weights!

Can somebody explain why this might be happening?
 
You are lighting up the powder better with the 450s and in the process, if you chronograph the loads are prolly getting a better ES and maybe SD.
 
Since the two primers are identical (according to CCI, who told me on the phone they have the same amount of the same priming mix and identical cups) except for the anvil legs having a wider angle in the #41 to bring sensitivity down to military spec, you are probably seeing inconsistent ignition either from inadequate firing pin energy or from failing to seat the #41's adequately, which takes a little more effort to do. The shorter anvil means they need to go slightly deeper to have the same bridge set. They should, ideally, but pushed in about 0.003" past the point where you feel the anvil touch down against the floor of the primer pocket.
 
if you chronograph the loads are prolly getting a better ES and maybe SD.
I should have mentioned this. ES and SD have been dramatically improved.



It might be my priming technique, but I have made a lot of good ammo on this lnl press. Some with #41's.
 
Alan Jones, who used to develop primers for CCI backed up what the late Creighton Audette wrote in the early 90's, that you can get ignition delays and related phenomena with improperly seated primers.

You want to make some measurements to see if the priming is falling short. A depth mic with 4 mm diameter probe is best for determining the depth of your small primer pockets. The depth probe that sticks out of the end of the beam on your caliper may be used, but it is challenging to get consistent readings because it is hard to get the bottom of the caliper perfectly square to the case head unless you have a depth adapter. (CDCOtools.com has one for $10, but their site won't let me link to it directly: Measuring Tools tab | Calipers and Attachments, last item.) Without it, it may take several attempts to find a believable reading, but it can be done. Once you have that reading, measure the height of several of the #41 primers. Subtract them from the depth of the primer pocket, then subtract another 0.003", and that will give you the correct depth below flush with the case head and into the primer pocket they should be when properly seated.

Short of all the measuring, you may also be able to fix this just by priming hard.
"There is some debate about how deeply primers should be seated. I don’t pretend to have all the answers about this, but I have experimented with seating primers to different depths and seeing what happens on the chronograph and target paper, and so far I’ve obtained my best results seating them hard, pushing them in past the point where the anvil can be felt hitting the bottom of the pocket. Doing this, I can almost always get velocity standard deviations of less than 10 feet per second, even with magnum cartridges and long-bodied standards on the ’06 case, and I haven’t been able to accomplish that seating primers to lesser depths."

Dan Hackett
Precision Shooting Reloading Guide, Precision Shooting Inc., Pub. (R.I.P.), Manchester, CT, 1995, p. 271.
 
The CCI #41 primer is just a magnum primer. Ramshot Enforcer doesn't need magnum primers.
And there is no "~" when it comes to powder charges either. However, you're probably seeing very small pressure differences.
Isn't a good idea to switch components in the middle of developing the load. Nothing terminally dangerous about it. Just that everything needs to be the same throughout the process. The theory is that if you change any component you need to start over.
 
I don't think he's necessarily looking for a magnum primer, but rather to have the military sensitivity characteristic for his floating firing pin gun. To get a military sensitivity spec primer, you currently have only two and maybe three choices:

CCI #41
TulAmmo KVB223
Federal GM205MAR

The first two are magnum, same as standard military primers. The reason the military uses magnum primers is not based on powder but on their -65°F firing function requirement, as they used them with 4895 as well as later ball powder. The TulAmmo primers seem to have disappeared, though, so I don't know if they got out of that business or not. The original tulammousa.com site seems to be gone.

The last one is the same as the Federal standard power Federal GM205M, except the AR suffix means it is intended for AR type rifles with military sensitivity specifications. In Federal's case, I have an email from them that explains they achieved the military sensitivity specification by thickening the cup rather than by changing the anvil, as CCI did. Powder Valley has them in stock at the moment.
 
Thanks T....Maybe I wasn't clear. I started over with 450's.

~17.9 means I have tested min to max and am settling at 17.9gr EXACTLY as my most accurate loading.....unless I keep testing, but I'm happy enough at 17.9. I'm going to make 50 to confirm tomorrow....
 
Unclenick, I see what you are saying, but I get good accuracy from the #41's in my 5.56 55 gr plinking load....same priming setup....same loader.

I think it is related to the primer spec relative to what the 300 BO and Enforcer powder require.
 
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