Primer Seating Depth Causing Light Strike? Dillon 550B

[Smitty79]

I shoot a CZ Shadow (91030) with an 11.5# main spring and CGW extended firing pin and reduced power firing pin spring.    The CZ community tells me that this set up should reliably pop any high quality primers.   The gun is 100% on Fed, about 1% light strikes on Win and 2%+ on anything else.   Virtually all light strikes go bang on restrike.   I think I have a seating problem.

I have a 550B.   I try to seat the primers pretty hard.   Is there anything I can do to try to seat them deeper?   I've read that a loose shell plate can cause this.   If I tighten the center bolt more, it's too tight to turn easily.

Any ideas?

[nicky]

I think what they mean is not the plate that you use to move the case to the next station but the plate underneath that. That plate could be loose. There are 2 bolts there to tighten.

[Tok36]

Smitty have you inspected your firing pin and firing pin channel to insure that nothing is impeding the FPs travel? I might cross this off the list. I cannot comment on the primmer seating depth, i run a 550 as well and i have yet to encounter any light strikes with the 11.5# hammer spring. Up to this point I have never considered primer seating depth i just put the primmer in the hole. 

Anyways, interesting thread.

[SI VIS PACEM PARRABELLUM]

I tumble polish my brass after sizing and de-capping and EVERY primer pocket gets brushed clean before a new primer goes in. Yea it's an extra step but that's the way I choose to do it.
Also how old are the springs in the gun? The mainspring can weaken over time and sometimes you get one that just doesn't live a long life no matter where it came from.

[Bossgobbler]

Have you measured how deep you are seating the primers?  Should be .002-.006 under flush.

[Smitty79]

Main spring is new. It will pop a pencil all the way out of the barrel when held vertically. 

[ReloaderFred]

It does sound like a seating depth issue if the rounds will fire on the second attempt.  The first strike is finishing the seating and setting the anvil into the priming pellet enough for the second strike to actually crush the pellet and make the primer detonate.

My seating depth is -.004", and I clean all primer pockets prior to seating new primers.  I can clean 1,000 primer pockets in about 40 minutes with my setup.

I can't help you with adjusting the 550B.  I had two of them brand new and sold them both.  They just weren't my cup of tea.

Hope this helps.

Fred

[1SOW]

It has been said that politics is the second oldest profession.
I have learned that it bears a striking resemblance to the first.

LIKE!

[Wobbly]

I have a SP-01 set up with 12# recoil and the lighter (8# ) hammer spring. I use Fed #100 primers installed by a Dillon 550. I never ever clean primer pockets. I shoot mixed brass. I can't even remember when the last time I had a light strike was.

I stack my finished ammo bullet-nose-down in the plastic case, then run my finger over them to insure each primer is recessed. That's all.

I highly suspect the springs.

[Wobbly]

Rigidity of the press mount has a lot to do with the ability to seat the primers to the optimum depth and sensitivity. More so than most people think or realize.

I've been thinking about this statement and I have to agree.

You've got a good press that should give good primer seating, but how is the press mounted? Do you use a Strong Mount? The SM certainly does give the 550 a much better stance upon the bench top. Is the press situated over a leg of the reloading bench, or out mid-way between legs ? Bench tops can flex a substantial amount. It may feel like you're applying heavy pressure, but in reality all that energy can simply being consumed by bending the wood beneath the press.

It's an area of study engineers call "Statics".

 

[Smitty79]

I posted this question on Enos too.   The guy from Dillon chimed in that I should tight the screws under the platform just pass the primer catcher.   If the one on the left isn't all the way tightened down, it can block the press motion when you are seating the primer.   I got about an eighth of a turn out of it.

Ammo I loaded before this tightening had typical seating depths from 0 to 2 mils.    Now I'm getting 5 to 7 mils.    I need to load up a few hundred rounds of ammo and check it out.

[Wobbly]

That's good news indeed !  Still, don't ignore the need for utter rigidity in the whole press mounting.

? The use of a Strong Mount allows the press to be set back onto the bench top by 6 inches, instead of perched precariously hanging out over the bench top edge. The difference in added stability is unbelievable !

? The single best thing you can do for any press setup is to place the press directly over a table leg, or, if you want your press in the middle of the bench, to add a table leg under the press. In this way any downward force applied to the op lever is channeled directly into the concrete floor.

The object of both these moves is to have ALL of the energy you expend going directly into the cartridge. Right now, it sounds as if you're loosing about 20% of your physical labor. That lost labor is doing "work", but the "work" is merely to flex the bench top. The wooden bench top acts like a spring and absorbs (wastes) your physical energy. If you stopped all bench movement through better bench support, then you would reduce the energy YOU expend by that same 20%. In other words, you could load better ammo with only 80% of the physical labor.

I tell you all this because commonly, people expending that much physical energy often have arm and back pain issues they don't always associate with reloading. That soreness and pain is absolutely and positively needless.

Here's my bench...


Ignore the SDB which was temporarily mounted for testing. Look under my 550 and you'll see a whopping 4x5 timber as a bench leg. The weight of the leg won't let the bench rise up on up-strokes, the rigid support of the leg won't allow the bench to flex downward on down-strokes.

That's the kind of rock-solid press support you should work toward.

 

[Smitty79]

I have the strong mount.  I guess I need to move my press.

[Tok36]

So Wobbly, you are saying that your 550 dose not Wobble? 

[Wobbly]

I have the strong mount.  I guess I need to move my press.

There are a lot of ways to achieve stability, and to get there sometimes you need to think "out of the box".

Primary consideration: Due to the way the press operates, you need stiffness (or resistance to movement) up-down, left-right, and front-back. IOW, 6 axes of support in order to achieve a rock-solid support.

? If you think about it very long it may occur that the only thing on the bench that needs support is the press. Everything else, the books, calipers, primers, powder, etc. could be supported by the flimsiest of tabletops. So the cheapest thing to do is to build 2 benches side-by-side. One super strong mini-bench for the press, and then one large shelf / tabletop to support the reloading supplies, both at the same height for your convenience. This has the advantage of concentrating the cost at the point of need.

? Additionally, while some materials may need to be scrounged up, you should take advantage of existing "stiffness" to reduce your material requirements. If your bench can back up to a concrete block wall or a sheet rock wall with studs, then the existing wall can can be utilized to absorb 4 axes: left-right and front-back. Therefore, the mini-bench only has to be 20" wide to grab 2 existing wall studs. So for the cost of 2 large steel L-brackets to attach to the wall, you've saved a lot of other material costs.

? So then, the only 2 axes remaining to be subdued are up-down. As previously discussed, this is easy to do with a single, heavy bench leg directly under the press. The single leg could be a tree trunk, large treated timber, scrap wood from a shipping pallet, or several 2x4's glued together. This type material is in every construction dumpster; there's no need to buy anything.

? Lastly the new benchtop needs to resist bending. The easiest way to do this is layer 3+ thicknesses of 3/4 plywood. The one on the top (showing) can be nicely finished, but the interior layers needn't be anything more than rough particle board. The secret is to glue (Liquid Nails) all the pieces together and then screw them together from the underside. You can finish it off by adding some nice trim to the edges to help conceal the layers.

? So the sturdiest, cheapest way to go is going to end up looking like this...