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<  16ga. Ammunition & Reloading  ~  Beginner question about 2.5 vs 2.75
pjourn
PostPosted: Fri Aug 10, 2018 8:29 am  Reply with quote



Joined: 04 Sep 2007
Posts: 49
Location: Idaho

Long time listener, first time caller.

So I have a press, I have a boatload of 2.75 cheddite hulls (heaters), I have a roll crimper...

I want to shorten my hulls to 2.5 and roll crimp. In the interest of simplicity, I'm going to use one of the hogdon reloads. (Universal powder, cheddite primer.)

The question is, if I roll crimp, can I use a load for 2.75 in a trimmed hull? I.E., can I use an ounce of shot and g/bp16 wad in a 2.5 roll crimped cheddite?

I'll follow to published loads, but I'm unsure how length and roll crimp vs fold crimp impact loads.

If someone has recommended reading material, I'd appreciate it.

Thanks so much
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rudolph31
PostPosted: Fri Aug 10, 2018 8:59 am  Reply with quote
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I think roll crimping is difficult at best; roll crimping a previously star crimped shell may well prove impossible. But there’s an easy alternative. Don’t use your Short Kit; load your short shells normally, put an overshot card on top, then star crimp it in place. If your hobby is shooting and not reloading it’s the way to go.

Here’s a thread on the subject:

http://www.16ga.com/forum/viewtopic.php?t=15465&highlight=hartin
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byrdog
PostPosted: Fri Aug 10, 2018 12:09 pm  Reply with quote
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I roll crimp with a small drill press. I set it up to get the crimp I want and do a box at a time. I use a loading block to hold the loaded cases doing one after another . If you want to fold crimp shape a 1/4" thick piece of plywood or masonite to fit under the bracket on a MEC loader amd crimp away.

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Brewster11
PostPosted: Fri Aug 10, 2018 1:21 pm  Reply with quote



Joined: 08 Feb 2009
Posts: 1301
Location: Western WA

Once fired Herters hulls make EXCELLENT roll crimps if you use the Precision tool and a drill press, and you can fit 2 3/4" loads into hulls trimmed down to 2 1/2" and then roll crimped. Unfortunately the process is extremely tedious and time consuming compared to standard fold crimps. So we reserve roll crimps for limited specific hunting loads such as non-toxic shot.

We tried the so-called Hartin crimps (fold crimps on reduced length hulls) and while they form easily, look good and hold full-capacity loads, our chronograph tests showed very poor consistency with velocity. There may not be enough resistance in the crimp to develop proper pressure. Or maybe our Hartin crimps were too shallow, who knows. Yes they go bang but we gave up on them.

Our best result was to load 2 1/2" hulls with 2 1/2" loads. Plenty of excellent 2 1/2" loads are published using standard components. And the SG16S wad from BPI and elsewhere provides more room than standard wads. So maybe you should consider loading your 2 1/2" hulls the way they were intended to be loaded.

B.
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Hootch
PostPosted: Fri Aug 10, 2018 2:46 pm  Reply with quote



Joined: 28 Mar 2008
Posts: 1460
Location: Eagle, Nebraska

I use a load in short hulls that is for 2.75 hulls and fits fine, that doesn't mean all load recipies will, but this one does.

You can buy short hulls from Precision Reloading, be new and easier to crimp and no hull cutting.

My load is an 1-1 1/16 using long shot and the z16 wad.
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pjourn
PostPosted: Fri Aug 10, 2018 2:52 pm  Reply with quote



Joined: 04 Sep 2007
Posts: 49
Location: Idaho

Isn't there more available volume in a roll-crimped shell as opposed to a fold crimped shell?
I guess I was thinking a roll-crimped 2.5 was closer in volume to a fold crimped 2.75 than to a fold-crimped 2.5.
I'm looking at a pretty simple, 1 ounce load.
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putz463
PostPosted: Sat Aug 11, 2018 2:30 am  Reply with quote
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Which press do you have? By and large I concur with Brewster11's post. Exception; I've never tried the Hartin Crimp, by the looks of them I fear a pocket of loose shot after a day of roaming around chasing bird's-n-bunny's.

"I guess I was thinking a roll-crimped 2.5 was closer in volume to a fold crimped 2.75 than to a fold-crimped 2.5."....

You're thinking correctly, Roll Crimping allows the maximum available space in a hull compared to Fold Crimping. RC needs ~1/8" of free hull wall for the crimp to work and FC ~1/4".

"The question is, if I roll crimp, can I use a load for 2.75 in a trimmed hull? I.E., can I use an ounce of shot and g/bp16 wad in a 2.5 roll crimped cheddite?"....

More than likely, might have to change the wad to the short version or apply a bit seating pressure to break/squish the wad legs a bit.

Do you have a short chambered gun that needs 2.5" shells?

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MaximumSmoke
PostPosted: Sat Aug 11, 2018 7:56 am  Reply with quote
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pjourn -- You have good questions. I will address your post point-by-point:

First, I assume you want 2 1/2 inch shells for a good reason- chamber length or something. I will ask you why you don't want 2 9/16 inch shells (65mm) though, as that is the more typical chamber length. Actual 2 1/2 inch chambers in the 16 seem to be the sole province of a few old British doubles, in my experience. I know its only .062" more, but you will be happiest using all the hull length you can -- you may even want to go to 67 mm or 2 5/8" -- your 2 9/16" chambered gun will never know the difference. By the way, today's Remington Game Load (RGL) hulls are 67mm, and you can crimp them just fine in a MEC reloader, and most others, too, I'm sure. B&P also sells 16 gauge shells in 67mm. Check other shells for length before you go slicing off a quarter of an inch will-nilly. Most US manufactured 2 3/4" hulls in the past are short of that by a little bit. I know it isn't the same gauge, but for example, current Winchester AA-HS 28 gauge hulls sold as 2 3/4" (70mm) are actually about 66mm, and the earlier versions of the 28 ga. AA-HS were 65mm. The AA-HS 20 gauge hull is also short by a couple of millimeters.

Before I goo further, I will also ask you why you don't pick a load that fits into a star-crimped 2 9/16 inch Cheddite/Fiocchi/Martignoni type hull, buy the right wad and go with that. By filing out the slot on the crimp cam of a MEC reloader (the cam of all current MEC's controls the length of the finished shell), I can star-crimp 2 9/16 inch 16's. You could just trim your Herters hulls 5 mm (about .2") or whatever it takes to get to 2 9/16", and star crimp them, roll crimp them, or use the Hartin crimp.

Those who decry the Hartin crimp are either 1) unnecessarily removing too much hull length, and/or 2) lacking understanding of the appearance of a proper Hartin crimp. FYI, it looks just like a standard pie/star crimp, but with a little hexagonal or octagonal (depending on whether the hull originally had a 6-point or 8-point crimp) hole in the middle, under which lies the same type of overshot card used for roll crimping, which closes the hole. Crimp depth is important. Too deep and the hole is too big, too small and the crimp is not firm or strong enough. Hulls loaded with these crimps turn out to be loaded to the same height as they were originally. That means the "memory" of their former crimp is still in the same place, and such trimmed hulls can be reloaded several times with the Hartin crimp.

Now we come to roll crimping. Certainly, you will be able to get the same load as a 2 3/4 inch hull will hold into a roll-crimped 2 9/16" hull. Certainly you can be successful with roll-crimping a used 70mm (2 3/4") hull that has been trimmed to 2 9/16". Byrdog makes a nice, easy to use trimmer, by the way, or you can figure out how to make a dowel-and-Xacto blade cutter yourself. You'll want to make sure the hull mouth is fairly round before you start the crimp, but as I recall, those Herter's hulls open up nice and round on firing, not like Federals, especially the older ones, which sometimes retain quite a bit of their "pre-crimp" star shape after firing.

Roll crimping is NOT difficult. Usually, you can hold the hull by hand on a flat bench top and use a roll crimp tool in a hand-held drill and get the job done nicely. Like Byrdog, I use a small drill press for ease and uniformity, and higher volume production, but you don't absolutely need to. One thing you should be aware of is that roll crimped plastic hulls remain fairly ripply around the hull mouth after firing, and this limits reloadability afterward -- it doesn't necessarily eliminate the chance to reload that hull again, but certainly reduces the times it can be done to a very small number. One more thing -- I advise against using the single-pin roll crimp tool from Ballistic Products. I am not alone in this. It will be very frustrating. There are better tools out there. Something with 3 or 4 "lumps" or "ramps" in the groove of the tool is easier to manage and will likely produce a better crimp with less mechanical and heat stress to the plastic hull material -- which means you can reload that hull more times.

So what does roll crimping do to ballistic performance? From data I have seen ( I have not produced data) hobby-loaded roll crimping tends to lower pressures and velocities, and decrease the uniformity of loads. Peak pressures seem reduced to a greater extent than velocities - that's nice. All these effects are usually inconsequential to the shooter, and nothing in these variations makes things harder on the gun. That means roll crimping a load intended to have a good hard star crimp does not move things in an unsafe direction.

Happy Reloading!
Tony
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gjw
PostPosted: Sat Aug 11, 2018 9:14 am  Reply with quote



Joined: 09 Sep 2006
Posts: 863
Location: NoDak

Hi, contrary to popular belief, you can shoot 2 3/4" shells in a 2 1/2" chambered gun. There are some caveats to this of course. Here is an article that covers this subject very well, and will disproved some of the myths about long shells in short chambers:

file:///C:/Users/Wesbutte/Downloads/Shotgun%20Pressure%20(1).pdf

(You'll have to copy and paste the above link, won't open on it's own, sorry!)

In fact I'm reloading some LP loads in 2 3/4" Cheddite hulls today. If you want the recipe I use let me know. I have one for 16ga and one for 12ga. I've used these loads for sometime without any ill effects to the gun or myself.

Good Luck!

Greg

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MaximumSmoke
PostPosted: Sat Aug 11, 2018 12:21 pm  Reply with quote
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Here's a good link: http://doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=400793&page=1

Make of it what you will.

My Phily Fox Sterlingworth had 2 3/8 inch chambers, which had very minimal forcing cones, and I shot 2 3/4 inch shells in it -- mostly the current one ounce factory Winchester Super-X low-brasser, and RGL's, neither of which is famous at all for low pressures. The only things damaged even slightly were the Super-X hulls - small choking down of the mouth of the hull. The RGL's are so short they never noticed the chamber length. This did not harm either of these hulls in the least for reloading. Later I had Mike Orlen open the chokes to make the gun more useful for my shooting, and in the process had him lengthen the chambers to 2 3/4 and ease the forcing cones. There was plenty of room. I hoped by this to make it pattern as well as possible. I accepted the current "wisdom" of long chambers and forcing cones, but truth be told, I have no data to verify improvements, beyond more open patterns more suitable to the intended ranges of my targets.

I used to shoot 2 3/4 inch papers in my grandfather's old Crescent Arms 12 gauge double, which had 2 1/2 inch chambers with virtually no forcing cone, and a fairly sharp edge at the end of the chamber. It would often clip off a portion of the paper at the mouth of the hull. No living thing or object beside or behind that gun died or was injured when it was fired, even with the standard high-velocity load. The gun was going strong when I sold it, and I would bet dollars to doughnuts (gee that is kind of an even odds thing today, I guess Smile it survives to this day.

And by the way, you will find many old US made doubles from the teens and '20's with chambers usually 1/8 inch shorter than the shells they were advertised to use, and of course those were the paper shell days.

So, Greg's advice above is safe, for me at least. I especially like Sherman Bell's articles. I like facts even better than my opinions and theories.
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pjourn
PostPosted: Mon Aug 13, 2018 10:46 am  Reply with quote



Joined: 04 Sep 2007
Posts: 49
Location: Idaho

Thanks everyone for your thoughtful and helpful advice. I do have some short chamber guns, so that's the impetus.
Tony, you are right. I don't really need 2.5, but rather 65 (or maybe 67) would be sufficiently short for everything I have.
My setup is a Lee Loadall press that I've used to make hunting loads for my citori and a roll crimper which I have never used.
I have read the information about longer shells in short-chamber guns.
My personal experience is that I like old guns (particularly french ones) and I restock and puts guns back on face as a hobby. In my experience, there are a lot of short-chamber guns that are shot loose or have cracked stocks. I wouldn't argue that it's unsafe to shoot 2.75 shells in 2" 5/8 chambers, but I would say it's not good for old guns. I've been buying short shells for years and thought I should start making my own. I shoot maybe 6 boxes of 16ga hunting loads a year, so I don't need volume production, just good loads.
I'm going to trim some hulls, and try some crimps (roll and Hartin) and see what works I guess! I also have short chambered 12 and 20 guns, so I guess the 16 is my test project.

Thanks so much everyone, I appreciate the thoughts and ideas.
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