357 Herrett Case forming

I have had a set of 357 Herrett barrels for some time. I have not spent alot of time working on this problem. The brass that came with barrels have a 50% misfire rate. I may have not properly resized the cases and moved the shoulders back.
So I am going to start over. I have some 30-30 cases to try and make a good set of cases. It there a way to blow out the cases without wasting more powder, bullet and time.
I should add this, this problem is with two barrels using an original frame and a G2 with same results.
My 30 Herrett works like a dream on the same frames.
Merry Christmas
Gerry

You can start with .38-55 or .375 Winchester brass instead of .30-30 will save you a fire form step. The down side is you may lose more cases to the forming step and the necks may get a bit thick. Also note that the misfires might be caused by the locking lug not fully releasing the safety block. You can test this on an original frame by closing the action and without cocking the hammer, pull the trigger. Pull back a little on the hammer and you should hear a light click and release the hammer. It should fall flush with the frame. If it not then you may need to take a couple of thousandths off the bottom locking lugs to get them to go deep enough push the safety off.

When I formed 357 herrett brass I ended up doing things differently. I fireformed full length 30-30 with some pistol power and some type of filler (cant remember what). Then I would trim most of the excess length off with a dremel tool and finish trimming with a case trimmer. The only time I ever got misfires was with a 7mm tcu that I was neck sizing. I now think that contenders need a fully sized case, there has been alot written about this.

I recommend getting a trim die

I don't know what you are using to form the cases, but I played with a 357 Herrett years ago. I seem to recall that I started by using the loading dies, and adjusting them as someone else mentioned until the gun closed snugly on the case, but also locked up so that the hammer would fall. As far as trimming, I initially used my RCBS lathe trimmer. However, I did later on get the case forming dies that included a trim die, this was much easier. My 357 herrett is long gone, but I may still have the case forming dies around here somewhere. If you want to try them let me know, I have no use for them now.

I have a set but thanks for the offer.
Long winter coming, I will have it solved by next spring or bve looking on Gunbroker for barrels and dies.

Try loading some with mid-level load and pistol primer.

Herrett's are supposed to headspace on the rim, not the shoulder.

Of course once I shoot mine, I never fully size them again.

I have never had a misfire.

I use Large Pistol primers for all my cast loads.

In my 357 Herrett, which is also long gone, Im almost certain I could close the action on unsized 30-30 brass. my logic was that the neck would be more uniform from trimming a fire formed case. Im not sure if I was right.

I really liked the 357 herrett, I was a fool and sold a fantastic hunting barrel, accurate and fast. A few years later I got a custom .357 Maximum. The brass is easy on the max but the herrett is every bit as good.

I don't understand

Your Herrett does NOT headspace on the rim?

that sounds like a gunsmith issue to me.

what am I missing?

Herretts are a rimmed case (obviously) but if you headspace on the shoulder your brass will last way longer. If you run cases up all the way into the sizing die, it sets the shoulder back excessively, that, added to the "spring" in the action will cause work hardening of the brass as it is fired and expands in the chamber, then is resized pushing the shoulder back yet again.

Next, accuracy goes south because the brass hardens inconsistently, causing inconsistent bullet pull and accuracy problems.

After a few such cycles, the brass fails

Annealing will prolong the life of the brass, but it's better to just adjust the dies so that it fits the chamber, that is so the loaded round is a 'snap fit' in the gun, so as not to blow it out each firing and excessively work the brass.

Hope that makes sense, sometimes I'm not so good at communicating details about interior ballistics.

According to the instructions with the forming/sizing dies, both the 30 and 357 Herrett are designed to headspace on the shoulder. This is why the forming and first firing is so critical. After forming, you should back the die off at least .040".
I have used the 30 Herrett with success for years. Hope to have the same success with the bigger brother this Spring.
I will inform on success unless I get off on another tangent.
Happy New Year
Gerry:drinks:

Quote:

---

Originally Posted by Leadmelter

The brass that came with barrels have a 50% misfire rate. I may have not properly resized the cases and moved the shoulders back.

---

This is almost certainly correct. If your cases are in good shape, resize them correctly and they will work fine.

Quote:

---

Originally Posted by Leadmelter

So I am going to start over. I have some 30-30 cases to try and make a good set of cases. It there a way to blow out the cases without wasting more powder, bullet and time. ... My 30 Herrett works like a dream on the same frames.

---

Your 357 Herrett should also. My experience is that cases that have been formed but not fireformed will produce quite satisfactory accuracy with starting loads. You shouldn't worry about wasting components, just use the components.

Take care, Tom

Quote:

---

Originally Posted by Olevern

Herretts are a rimmed case (obviously) but if you headspace on the shoulder your brass will last way longer. If you run cases up all the way into the sizing die, it sets the shoulder back excessively, that, added to the "spring" in the action will cause work hardening of the brass as it is fired and expands in the chamber, then is resized pushing the shoulder back yet again.

---

but if it HS's off the rim, how can there be misfires?

As leadmelter said, the rounds HS off the shoulder.... BUT that brings up a significant SAFETY hazard. Using a rimmed round with an excessively deep recess in the chamber. Does EVERYONE know to ONLY HS off the shoulder?

seems to be a bad design if that is the case.

if that is the case, maybe it would be better to sub a rimless case, such as a 30Rem instead?

Leadmelter, I think I have a set of the old instructions for reloading ammo for the contender that came with the gun. It does have some info on forming Herrett shells. Email me, and I can send you a scan. I think the PDF I have has some of the pages doubled up, but I think it might help you just the same.

Doug

with a rimless case if one sizes too short you can drive it deeper in the chamber ( usually and hopefully only a misfire will happen ..well other than the reduced brass life once you get it to fire ) headspace is critical on all contenders - especially for longer case life , heck even my 10 mm seemed weak ,not very accurate and worthless until i loaded it more like a rifle as opposed to a pistol . a trick for too short of brass is to jam a boolit into the lands to hold the case against the breech thus making only the neck stretch as opposed to the web where they seem to get weak and later fail , if you set up your dies just right you dont have to back off any just lock it and leave it ( tho some do prefer the slightest of shoulder bump ) the procedure has always been the same , start with brass too big ( such as the parent case the 30-30 ) size it so it's still too long trim to length and then slowly adjust the die down a lil bit at a time ( i go 1/8 of a turn ) until the action just barely "snaps" closed on the case , this should be zero headspace , the snap isnt a gentle closing but as it sounds a sharp snap , if you wish a lil shoulder bump turn it in 1/16 of a turn more , done this way you can use a fast burnong powder and cream of wheat with a soap or wax plug to fire form , i used to do that but now i use what else but boolits i cast :P i too suggest the much stronger 375 win case !!! even with good lube i've lost a few cases trying to neck up to 357 from 30-30 , i'm sure an intermediate die would help ( or a really awesome tapered expander - IMHO both rcbs sets i've had were a lil blunt with a rounded nose and knurling )

Usually missfires in a Herrett means that the shoulder is too far forward blocking complete lock-up. If the case is the right length (to shoulder) or shorter, the rim insures ignition.

This was a wildcat cartridge and wasn't originally intended by the designers for commercial production, but the word got out, magazine articles were written, and the chambering was added to the Thompson Contender line.

I think (As in speculate) the assumption by T/C was that anyone who was competent enough to form and fireform cases, would be advanced enough in reloading to fit the cases to the chamber.

No, I'm not on the board of Thompson Center, and this is only speculation on my part, based on no facts or research.

Anyway, both the Herrett cartridges are fine cartridges and worth a bit of tinkering to get it right in your particular chamber.

I only wish Thompson Center had paid more attention to a proper throat in these barrels, as in many of their chamberings the Herrett barrels are known for an abrupt 'leade', 'throat' or transitioning from the end of the chamber to the rifling. This, and having too long a chamber, so that it takes a really long boolit to get it anywhere close to the abrupt end of the chamber and start of the rifling.

I've played with a number of them over the years and all except a Texas Contenders barrel had this problem.

If you use a long boolit to get close to the end of the chamber (where the rifling begins) you have too long a boolit for the twist, which was made for shorter jacketed bullets. Accuracy suffers.

I have found, in general, that jacketed bullets work best in the herrett barrels and most shoot well with jacketed, even with the long jump to the rifling. Cast boolits, at least in my experience, do not fare as well.
Jacketed of 125 (Nozler Bt) and as heavy as 150 gr. have worked well for me in the 30 herrett.

As produced by T/C, these barrels have not proved (to me, in my experience) to be cast boolit friendly.
One of the problems I have seen is that a cast boolit, released too far from the abrupt transitioning point to the rifling, slams into that leade off center, shaving off lead and mis-shaping the boolit. After a few rounds, the lead builds up at that point needing to be removed before excess pressure occurs with firing another boolit thru it.

Someday, I would like to have a custom barrel maker make up a 30 herrett barrel for me that has a long enough neck to accomodate the longer cast boolits without the shanks of the boolits intruding below the neck and still be able to crimp in the crimp grove. With the custom barrel I could specify twist as well,(perhaps 1 in 8") to optimize accuracy with the boolits I would want to use (primarily the Lyman 311041)

Only my personal opinion and experience, YMMV, not responsible for .....etc. etc.etc.

EXCESS headspace is easy to determine. Simply fire a primed but otherwise empty case in the gun. Measure the amount of primer protrusion after removing the fired case. That is your headspace.

INSUFFICIENT headspace is harder to detect. Read Mike Bellm's treatise on how to measure headspace with an empty gun. It involves feeler gages, and removing the extractor, (or dismounting the barrel so the extractor can fall back into its' recess).

I had a Hornet barrel with excess headspace. Fix was to ream it to K-Hornet and headspace on the shoulder. It now shoots like a maiden's dream, and brass lasts far longer, too.

I would NEVER recommend dressing the locking lugs on a 'Tender barrel under any circumstances, until you eliminate all other possible factors. If the gun will fire at all, the lugs have engaged enough to push the safety out of the way, and that's enough.

Also have a .30 Herrett barrel that I will play with someday. Low priority for me - I can't use it on deer here in Slowhio.

Misfires are more likly the shoulders aren't bumped back enough. Just take the barrel off and put in a sized case if the head sticks up more than a couple thou. past the end of the chamber you need to bump them back. You may need to dedicate a frame for a barrel. I had my 30 Herrett on one frame , when I bought a new frame and tried it, the barrel would not shut . I had to bump shoulders on back everything I had on that frame

OK, thanks guys

it makes some sense now....

I have shot a 30 Herrett for may years and just bought a 357 Herrett barrel a few days ago. I have not been able to find the case length measurement for the 357 Herrett. Can anyone provide me this information?

Quote:

---

Originally Posted by Alaskantmb

I have shot a 30 Herrett for may years and just bought a 357 Herrett barrel a few days ago. I have not been able to find the case length measurement for the 357 Herrett. Can anyone provide me this information?

---

try glooming this link ( save some of my bad typing lolz ) it even has a limited amount of data
http://www.reloadbench.com/cartridges/w357herr.html

Try this.
http://www.loaddata.com/members/sear...etallicID=1861

You may find something on this site also. It's a great site for casting. I have not searched the site for 357 Herrett.
http://www.lasc.us/

Hornady says Max Case Length 1.750" trim to 1.740"

Someone came up with a case design that effectively took care of TC's lousy "leade" by cutting a new longer neck.

I have a 3 die set of Pacific dies and only neck size. The people in the know say to not do that but it works great for me.

I have also set the shoulder back on a few but if you put a piece of dental floss under the rim and fire it will re-resize. You can also set a boolit out too long and let it set the headspace that way and fire. Love my 357 Herrett and while a tad picky its a heck of a round. I just wish it sized off the rim.

I have formed .357 Herret cases using Starline 38-55 brass. The brass has fairly thin necks and sizes down pretty easily. You will have the advantage of not needing to fire form if you are careful with setting the shoulder to proper length. I did not need to anneal first but if you get some hard brass then annealing might be needed. I did not have any problems with mine other than getting the shoulder length correct.