[Rastoff]

My normal recipe is:
Win AA
Fiocchi 209
1oz lead shot
18grn Red Dot
DRA-12 or CB1100-12

According to Alliant this will be approximately 8,600psi peak pressure in the chamber.

I've recently considered loading some el-cheapo Fed hulls. They require the CB6100-12 wad due to the straight wall. While researching the recipe for this I find that I can use everything the same (except the hull and wad), but the pressure is down to ~6,430psi.

My question is this, why is the pressure so much lower? Is it due to the straight wall vs tapered walls of the hull?

I like the lower pressure. If I can get the same performance out of my shells by switching to this then I may never go back.

 

[Curly N]

My normal recipe is:
Win AA
Fiocchi 209
1oz lead shot
18grn Red Dot
DRA-12 or CB1100-12

According to Alliant this will be approximately 8,600psi peak pressure in the chamber.

I've recently considered loading some el-cheapo Fed hulls. They require the CB6100-12 wad due to the straight wall. While researching the recipe for this I find that I can use everything the same (except the hull and wad), but the pressure is down to ~6,430psi.

My question is this, why is the pressure so much lower? Is it due to the straight wall vs tapered walls of the hull?

I like the lower pressure. If I can get the same performance out of my shells by switching to this then I may never go back.

It is most probably due to the increased combustion area. Don't stockpile those loads if you will be using them in colder (below 40F). The performance may go into the dumper.

 

[Bulldog50]

I believe you already have your answer, the strait wall hulls have a larger and different shaped area above the base wad where the powder burns. I guess it coud be best described as a strait cylinder, compared to a cone shape in tapered hulls.

I am surprised that the load is the same in a strait walled hull. Typically it takes more powder in a strait walled hull to achieve the same velocity.

I assume you are talking about Federal/Estate hulls. Be aware that many of these strait walled hulls have paper base wad, and can really only be reloaded a few (4-5 times) max. Federal also had some issues with the brass coming off of reloaded hulls when they were fired/ejected. Other European shells/hulls are hard to get consitant crimps.

 

[Rastoff]

Thanks for the info gentlemen.

Bulldog50,
Yes, I'm talking about the Fed hulls. Around here they are plentiful. I'm actually planning on only reloading them once. This way I can always have a new hull to reload. It is a grand experiment. I have no idea whether or not I will continue.

Curly,
I don't "stock pile" reloaded ammo. I'm far too lazy to load more than I will need for a week or so.:wink:

However, why would the performance go down due to temperature? Does the temperature dramatically affect the burn rate of the powder?

 

[Curly N]

However, why would the performance go down due to temperature? Does the temperature dramatically affect the burn rate of the powder?

I have noticed a far greater incidence of pooky loads in temps less than 45F, most especially with Fiocchi primers, a little less with Nobel Sports.. Lower pressure loads only make it worse, been there.

 

[Rastoff]

The only thing I know is that a lower chamber pressure is safer. Is there a chamber pressure "sweet spot" that we should be looking for? I don't want no "pooky" loads.

 

[Curly N]

The only thing I know is that a lower chamber pressure is safer. Is there a chamber pressure "sweet spot" that we should be looking for? I don't want no "pooky" loads.

If you are shooting a modern firearm, anything under the Allowable maximums suggested by Saami, is as safe as any other load that performs satisfactorily. Below that, you can get barrel obstructions. The higher pressure but acceptable loads do seem to perform more consistently.
Do what you wish but keep a knock out rod close. :mrgreen: Those reflectors on a tall stick work very well @ $2.00 from Home Despot.

 

[Rastoff]

As a reloader, this is why I like a break open gun.

 

[870shooter]

Rast, just save the pooky loads for the slow birds!

Actually, I use a recipe similar to your pressure using 700X, 15 grns, 2.5" Fed shell, Pink CB 12 wads, 7/8 oz shot, @ 1150-1200 fps. I have shot this load in game guns in Temps @ 20 with no pookyness.

Temps affect pressure greatly in Rifle cartridges, to the point where a load developed at 80f will be dangerous at 100+f. to the point of blowing primers. Altitude aslo works on pressure. Nowhere near the effects with shotgun stuff, as we are not at the operating pressures of rifle or handguns, but there will be some change based on heat and altitude. Generally the higher either goes, so goes the pressure.

 

[bprater]

I regularly shoot with a friend that loves the Fed MPL (the cheapies from WallyWorld) hulls. He loads Cheddite primers, 18.7 gr. of Red Dot, the CB clone of the Fed 12S3 wad an 1 1/8 oz. shot. He is a fierce competitor and a great shot. He is also 76 years old and has been reloading the Fed paper-base hulls for over 30 years.

I have no idea where he got this recipe (1st Ed. of the Lyman's Manual??????) or what the velocity or pressure are. I've asked him and he just says he doesn't remember, but he hasn't changed the bar or bushing in his MEC 600 since he started reloading/shooting this combo.

Point is, I'm reasonably sure you can reload and shoot these hulls in safety, so long as you continue to ensure no barrel obstructions occur. I'd call Ben Ammonette at Alliant Powder customer service if you have any doubts however.

 

[Republican]

I've recently considered loading some el-cheapo Fed hulls. They require the CB6100-12 wad due to the straight wall. While researching the recipe for this I find that I can use everything the same (except the hull and wad), but the pressure is down to ~6,430psi.

Heads up...

Alliant just copied and re-published Claybusters data for the CB-6100. The "first" generation CB-6100 data at that, - that is where that 6,430 psi came from.

There was a powder cup problem with the first CB-6100, so Ron fixed the mold to make the powder cup work, but he never re-published new data for the CB-6100"A". So if you were to use the CB-6100"A", the pressure will be higher than that 6,430.

The better wad for those Federals is the Claybuster CB-2100, and for 1-1/8th oz, the CB-2118 works very well.

I believe that the intent behind the CB-6100 wad was for the Euro's which can have varying base wad heights. That is to say, with the Winchester-style crush section of the CB-6100, it is more conducive to use wad pressure adjustments for varying base wad heights, whereas the stiff and stout swirly crush section of the 12S0/12S3 wad is not.

Use the CB-2110, and CB-2118 wads for the Federal hulls. If you want maximum performance, and willing to spend $10.70/bag (to your doorstep), then invest in some Gualandi GU-1225's from BPI.

My question is this, why is the pressure so much lower?

And the answer is, because those were Claybusters actual test pressures on a wad that (unknowingly) didn't work at that time they were published by Claybuster (and then copied by Alliant).

Bottom line is, since Claybuster changed, and modified the design of the CB-6100 (to make it the CB-6100A"), there really IS no accurate pressure data published for them anywhere. If you want data for them (for comparison purposes), you can either swag it by using data for a 12S0/CB-2100, or pay to get them pressure tested, or lean on Alliant or Claybuster to actually re-test them (unlikely to see that happen).

 

[dogchaser37]

deleted

 

[Republican]

2 items Moke,

First why are the Gualandis' better than the Federal 12SO, 12S3 and the Claybuster clones? If it because they fit tighter in the hull, that isn't much of a reason.

You do have a point, and I shouldn't make such sweeping statements without data to cover my butt (said data is coming).

I've seen your OEM 12S3 test data, and agree, that they were spectacular. However, (right or wrong), I just don't even think about OEM 12S3's anymore once I priced them out, - you see the price on them puppies ? I just don't see OEM 12Sx's as a viable option at all.

I have Claybuster 12Sx clones getting tested right now (compared to Gualandis'), but my preliminary home chrono tests does indicate that the Gualandi's have an edge in lower SD's than the Claybuster 12Sx clones (which, as you know, are already pretty good in their own right).

Second, the internal shape of the hull, the volume in the combustion area of the hull, base wad material and the primer placement have more to do with the lower pressure, than an overpowder cup design of a wad. You only have to look at steel shot wads to realise that the overpowder section of a lead wad is going to expand and seal, EVERYTIME, unless it gets damaged. 8,000 to 11,500 PSI, developed in less than a millesecond, will expand the overpowder cup.

Look over some loading data, with equal components and powder charges, a straight wall hull with a low basewad, of either paper or plastic always run lower pressures than tapered wall hulls.

What I was trying to convey is, that it was already known that the powder cup of original CB-6100 wasn't sealing (Ron already admitted that), and that the numbers posted are now null-n-void (something that Ron also admitted to). I know that straights have lower pressure than tapers, I'm just saying that the published numbers for the CB-6100 are lower than normal (or what you'd expect with the revised CB-6100"A").

A properly designed power cup will expand and seal, yes. But much like the current day Drf0/3's, the original CB-6100 wasn't doing that, - hence the lower pressure, and blooplyness. Ron was the first to admit that, and noble enough to re-work the mold to fix it. And of course, the CB-6100"A" actually does work now. Some of us just needs to get on the horn w/ him to harp on him about that old data that is still up on the Claybuster website, which is no longer accurate (as Ron himself even said). You are aware of the whole CB-6100 vs. CB-6100"A" situation a while back, yes ?

 

[dogchaser37]

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[Rastoff]

Interesting information. I do indeed have CB 6100-12A wads I think. At least there is a sticker added to the identification paper that has an A on it.

The pressure listed on the back of the paper is 6,550 for the same load. So, Alliant data is not a copy.

 

[Republican]

Again unless you test those wads with all the different powder, hull, primer combinations, the only thing you are learning is about the combination you are testing.

I realize that Mark, yes. Not reasonable that I could test each and every powder and primer combination under the sun for a particular suspect wad in question. BUT, when said wad doesn't work when compared to it's competitors clone, or it's clone parent, then it's a bad wad, period. Be it one powder/hull/primer combination, or n+1, n+2, n+3. That is the case with the Drf0/3, and that was the case with the original CB-6100 that I mention. Ron at Claybuster is a pretty straight shooter, and pretty knowledgeable on wads, and he was very upfront about addressing the powder cup situation on the CB-6100. He knows his stuff.

Blanket statements about all powder cups flairing out at 9K psi pressure simply isn't true. If it were, Ron at Claybuster wouldn't have had to re-tool and re-do the mold for the CB-6100, and we wouldn't have the current situation with the Drf0/3. The physical dynamics are a lot more involved.

One of these days you and I need to visit on the phone

I think that would be a great idea actually.

 

[Republican]

The pressure listed on the back of the paper is 6,550 for the same load. So, Alliant data is not a copy.

Look again, - it's identical. 6550, 6790,7910 for 18,19,20 gn's of Red dot (209A primer).

"back of paper" :

Alliant on-line reloading guide:

Same thing for Clay dot, Green dot, e3, and A.S., - it's all been copied directly from the paper.

For reference, here is the back of the paper that I posted when the CB-6100's first came out:

 

[dogchaser37]

deleted

 

[Republican]

I can't believe that a wad manufacturer would believe it wouldn't seal.

Actually, I'm annoyed at the opposite, - a wad manufacture who actually believes that a thick lipped, short lipped, undersized cup would actually seal.

Trust me, Ron at Claybuster didn't change the CB-6100 to the CB-6100"A" due to 'powder migration'. He did it because all of the complaints from the shooters of bloopage, of which was further exaggerated by cold weather (tale-tell sign of wrongly designed powder cup lip for given diameter and resin characteristics). Powder migration with big-flake powders like Hodgdon's Clays (and e3 for that matter) just isn't happening in these situations (I know, - I've tried to indice it). Besides, if you look at the CB-6100 vs. the CB-6100"A" situation, you will see that Ron didn't increase the diameter of the cup, - he increased the length of the lip.

You keep forgetting about the pressure.

I don't. If you test these things, you will see what is happening. The pressure is actually the dead give-away of a sealing problem.

One thing not to be overlooked is the ballistic "cost" associated with an inadequate cup design (for those that do eventually seal at, or after pressure peak), and that is blowby cost. if it takes 4ms to seal, how much gas (and subsequently pressure) was just lost between 0 and 4ms ?

And that's not to mention the situations where the cup lip never does seal completely.

 

[Rastoff]

Ah yes, I was looking at the other primer.