MEC 600 Jr Mk 5 and Buckshot issue

[CLP]

I decided to start loading 00 Buck but started having problems from the beginning.

Load from Lyman Shotshell Reloading 5th Ed. p 357.
Powder: HS-7. Charge: 31.5. Primer: Fed 209A. Wad Column: One B.P. BPGS, One 12ga 1/2" fiber under pellets, One 12 ga 1/4" fiber under pellets, and nine 00 Buck pellets. Should give a velocity of 1247 and pressure of 9400 psi.

Step 1: The depriming and base resizing step. No problems here except sometimes I have to jiggle the shell so the primer aligns with the hole through which the depriming pin travels.

Step 2: Priming station. I don't think there's a problem, but the primers don't have the same feel when being seated like cartridge primers (which I do by hand). They look flush and don't appear loose.

Step 3: Cutaway pic as shown. The BPGS gas seal is seated properly (such that the ridge fits flush with the cup in the shell). Everything else in this step looks good from what I can tell. I place 3 stacks of buck staggered atop one another by hand.

Step 4: Starting the crimp. Seems to be fine. I'm using the proper spindex.

Step 5: Crimping. The crimp looks acceptable- but not as good as factory new shells. The problem is with the bulge about 1/4" above the brass that develops during this process. See pics.

 

[CLP]

Additional pics

 

[Steve C]

You need to adjust your crimping station up a bit to reduce the pressure its putting on the case and bulging it during the crimping operation.

If you want an answer from the experts go to http://www.mecreloaders.com/ and on the bottom there's a number and an e-mail link for technical support.

 

[CLP]

yeah, i wrote them an email, just awaiting their response. I thought the last station might have too much crimp so i eased up on it a bit. However, when i ease up on it I get a poor crimp and there's still a bulge...will see what MEC says

 

[rbernie]

I thought that buck had to be crimped with a roll crimp and not a star crimp - no?

 

[CLP]

my factory loads are star crimped

 

[gamestalker]

Back the wad pressure off to about #10 and the problem will disappear. When you seat the components on top of the powder charge it getting compressed to much by the press at tht stage. The crimp could possibly cause that, but there would be more evidense at the crimp such as being inverted, and buldging would appear in the shot region of the hull as well. It's deffinitely the pressure applied when you are seating the those components above the powder.

 

[NCsmitty]

Your shot column is too high. Start by slicing one of the fiber wads by an 1/8" and see how the crimp and shell look. Adjust the cut to fit. Buckshot loads do not always fit the way the book lays it out. You may need to adjust your final crimp station a bit.



NCsmitty

 

[snuffy]

Smitty nailed it! Too high payload, not enough crimp space. That card wad is just stacks of paper, they're easily divided simply by slipping your fingernail into their sides. I would recommend cutting them in half.

Another thing, keep the wad pressure where it is or slightly INCREASE it. That will also give you more room up front. Bulged cases are ALWAYS caused at the final crimp station. The payload takes up too much space, the crimper piston tries to compress the wad column, The case bulges at it's weakest point, the powder charge.

 

[CLP]

I tried adjusting the crimper too. I cut the 1/4 wad in half- even omitted it too- on a couple of dummy rounds. I think the BPGS is getting pushed down into the plastic cup of the shell's base- I don't know if it should b/c it seems like it is supposed to sit atop it. When I ease up on the crimp station I get an incomplete crimp; and I tried crimping shells every 1/4 of a turn of the adjusting screw. Even with a mildly incomplete crimp I still get a bulge...

Will see what MEC says.

 

[rg1]

I agree that the shot column is too high. Try turning your shell in the final crimp step, lower crimper and release, turn shell 1/3 turn and crimp a little more, turn shell again 1/3 turn, and rotate again for the final crimp. It helps some. Are your AA's the new two piece hull? The 2 piece AA hull with the straight wall is just weak and won't take much crimping force or it will buckle. Does the BP gas seal sit right on the lip of the bottom section of the new AA hull? More compression of the gas seal on the powder column should help. The only hull I've had much luck with is the Federal hulls that are straight walled and not tapered, but I haven't tried the newer AA 2 piece hulls.

 

[NCsmitty]

I revisited the pics, and it looks like the gas seal lip is flaring out over the inner shell base piece, creating the bulge in the hull.
I initially thought that your final crimp was collapsing the hull, and it may be contributing, but the gas seal looks as if it is making the bulge.
I didn't see HS-7 in Hodgdon's shotshell load data and I'm wondering if you can increase the powder charge safely to keep the seal from bottoming on the inner base.
Maybe a flat over powder wad would eliminate the bulge, as it seems to me that your gas seal is not right for the job in that hull.



NCsmitty

 

[oneounceload]

Have you tried Remington hulls? Win hulls are two piece, Remingtons are one - your seal might be hanging up on that. You can also adjust the cam on the final crimp station a little to help with that crimp. Your photo with the buck in the hull - those pellets are way too high -the top of the loads needs to be below where the skives are on the hull