Break-open cartridge

[singleshot]

Opinions wanted please: given the fairly "springy" nature of a break-open rifle, what's the best cartridge for it? Headspace, taper, rim vs. rimless, etc, I've heard rimmed cases are best but most manufacturers offer few rimmed cartridges, 308 vs 30-06? It seems the greater taper of the 30-06 may compound problems in a break-open gun. Rimmed cases are much more difficult to control headspace without machining, but once the gun is "tuned" for correct headspace, it seems you're done, where you'd have to tightly control shoulder location with a rimless...

Ok, there's the teaser to get the cerebral juices flowing...

Thoughts please!

[williamwaco]

All my life I have heard and preached the gospel that break open rifles are springy and cannot be made accurate.

I can now witness to the fact that Thompson Center Arms has put that opinion to rest. I can see no difference in accuracy between my high walls and my TCs. Either will easily do sub-MOA.

That said, the bolt still beats them both handily.

[Crusty Deary Ol'Coot]

Singleshot,

Providing your not trying to over stress your firearm, I personally feel proper adjustment of your sizing die is what is needed.

Years back now, I had a 35 Remington in a Super 14 barrel which mounted to a contender frame a number of generations older then current production.

The 35rem has what seems to be a poor reputation for brass life, due in part to it's small shoulder.

When I bought the used barrel, it came with a box of fired Remington brass which was, as far as I knew once fired.

When sometime later, I sold the barrel, that box of brass, then 17 times fired was still going strong.

I shot normal .35 Remington loads in this "springy" break open action and feel that a major factor in the brass life I was seeing was due to proper setting up of the full length sizing die for that firearm/chamber.

That brass life was over the top! By any standard in this type of firearm and with this case.

The key here is on bottle neck cartridges, always size the minimum amount possible that will allow for smooth and relyable chambering of reloads, made from brass fired in YOUR CHAMBER and returned to your chamber.

Many times, brass is over sized, which leads to, at the least, very short brass life.

Keep em coming!

Crusyt Deary Ol'Coot

[singleshot]

Thanks guys.

I'm currently of the opinion that break-opens are "springy" but knowing and properly controlling the variables makes them as accurate as bolts. I think the problem has been the tendancy to try to get break-opens to shoot using the same techniques that we use with bolt guns (or none at all.) Trying to wring out any details that might help us understand the differences in this type of action is the goal.

I also don't see any reason that a high wall should be any less accurate than a bolt. I think b/c the industry focuses on bolts, that is where the knowledge and technology are focused, yielding the best accuracy "out of the box." Possibly combined with machining difficulty?

Now one thing I could easily buy, given equal cost of manufacturing, a bolt action is most accurate...but I'm not sure about that.

Recently, Mike Bellm put a few break-opens together that shot 1/4 & 3/8 MOA, not sure many bolts can out-do his results, but I'm not sure how much $$ he had in the guns either or how hard or easy it was to load ammo vs a bolt, or if that was the best he could ever do.

I can tell you that my break-open guns with tapered, rimless cases (30-06 style body taper) loaded 5-10% under SAAMI max pressures move the shoulder forward significantly with each firing and need to be repositioned with resizing...much more than any bolt gun I own. I've found that neck sizing is right out with that combo. Does that make that particular case less accurate? I don't think so, but again, not sure.

CDO, your results are consistent with my theories at the moment. The 35 rem is not tapered much and the small, steep angled shoulder doesn't give the cartridge much to push against the frame with, therefore, taking away some (most?) of the effect of the action.

The topic at hand remains: What are the best cartridges for break-open guns, and why? Maybe it doesn't matter? Again, why?

[Kraschenbirn]

My first .22 Hornet was a third or fourth-hand Savage 219 which was every bit as accurate as the Ruger #3 that replaced it. So far as brass life, 30-some years ago, along with that old Savage came a half-full coffee can of once-fired brass and a dozen or so 50-round boxes of milsurp survival gun ammo that I'm still reloading today.

In the 10 years I shot IHMSA and NRA silhouettes, I also put a lot of rounds through various TC Contender barrels, including a couple of fairly hot SSK wildcats, and found, essentially, no difference in brass life between rimmed and rimless calibers. As with almost all cartridge/gun combinations, the keys are to keep pressure levels within reason and neck-size only, once brass is fire-formed to your chamber.

Bill

[williamwaco]

Thanks guys.

I'm currently of the opinion that break-opens are "springy" but knowing and properly controlling the variables makes them as accurate as bolts. I think the problem has been the tendancy to try to get break-opens to shoot using the same techniques that we use with bolt guns (or none at all.) Trying to wring out any details that might help us understand the differences in this type of action is the goal.

I also don't see any reason that a high wall should be any less accurate than a bolt. I think b/c the industry focuses on bolts, that is where the knowledge and technology are focused, yielding the best accuracy "out of the box." Possibly combined with machining difficulty?

Now one thing I could easily buy, given equal cost of manufacturing, a bolt action is most accurate...but I'm not sure about that.

Recently, Mike Bellm put a few break-opens together that shot 1/4 & 3/8 MOA, not sure many bolts can out-do his results, but I'm not sure how much $$ he had in the guns either or how hard or easy it was to load ammo vs a bolt, or if that was the best he could ever do.

I can tell you that my break-open guns with tapered, rimless cases (30-06 style body taper) loaded 5-10% under SAAMI max pressures move the shoulder forward significantly with each firing and need to be repositioned with resizing...much more than any bolt gun I own. I've found that neck sizing is right out with that combo. Does that make that particular case less accurate? I don't think so, but again, not sure.

CDO, your results are consistent with my theories at the moment. The 35 rem is not tapered much and the small, steep angled shoulder doesn't give the cartridge much to push against the frame with, therefore, taking away some (most?) of the effect of the action.

The topic at hand remains: What are the best cartridges for break-open guns, and why? Maybe it doesn't matter? Again, why?



I am currently loading cast bullets in a Thompson Contender .30-30 to pressure levels according to Lyman of about 34,000. I am neck sizing with no trouble. BUT They are stretching more than any other cartridge I have ever loaded.

[canyon-ghost]

As with almost all cartridge/gun combinations, the keys are to keep pressure levels within reason and neck-size only, once brass is fire-formed to your chamber.



Can't say it any more eloquently than that. With my TC's, the old rule of thumb that I gleaned from Lyman Cast Bullet Handbook : Seat any bullet to .005"- .020" from the rifling for the best results.

I know, some people place the bullet to engrave from rifling, I've never made that work. It would seem especially troubling in a 40-60 round silhouette match.

[leadman]

I shoot Contenders, Encores, & Rolling Blocks. I have 2 Contender barrels in carbine length, 22 K-hornet and 223 Rem that are capable of .25" groups. I also have a 14" 30-30AI that has shot .25" groups more than once. My Encore Pro Hunter rifle in 7mm Rem mag will consistently shoot 2" 200 yard groups with the 150 gr nosler BT at 3,300 fps. I have shot groups at 485 yards of 4 to 5" with my 6mm PPC encore 15" barrel.
I measure the clearance between the base of the case and the breech with a feeler gauge and like to set it at .0015". The bullets are set right at the rifling. This way I get a gun that goes off when the trigger is pulled and the accuracy I want.
If you are measuring a dramatic increase in the cartidge length after firing with a known good load is it possible you are setting the shoulder of your case back too far when sizing?
I headspace all of my cartridges whether they are rimmed, rimless, or belted off the shoulder.
I have Bellm's gauge to check the cartridge in the barrel but find it is much easier to insert a feeler gauge at the base of the cartrisge case then close the action. If it pulls out real easy insert the next thickest, if it pulls hard insert the next thinnest until it slides out with just a little pull. It is best to remove the extractor the first time so you are sure this is not influencing the measuring.

[largom]

Once I have the cases fireformed to the chamber I neck size only and find my break open guns as accurate as most of my bolts. However, I do not load anything to the top end.

Larry

[singleshot]

IIf you are measuring a dramatic increase in the cartidge length after firing with a known good load is it possible you are setting the shoulder of your case back too far when sizing?
I headspace all of my cartridges whether they are rimmed, rimless, or belted off the shoulder.
I have Bellm's gauge to check the cartridge in the barrel but find it is much easier to insert a feeler gauge at the base of the cartrisge case then close the action.

Interesting! I'm pretty sure I'm setting the shoulder back close to the right amount if not right on...I kept pushing the shoulder back further until the rifle would close and lock, plus a smidge. The shoulders were far enough forward that the rifle wouldn't close and lock unless you persuaded it vigorously. (And that is a serious headspace issue.)

How do you headspace a rimmed case off the shoulder? Doesn't the rim bottoming in the chamber determine how far it will be? (Especially if it's too tight? Not so much if it's too long...) What about rim thickness tolerances?

I definitely need to try the feeler gauge method on a closed chamber, that right there is pure genius! :bigsmyl2: Thanks!

[singleshot]

Oh, I should mention I tried shooting some neck-sized cases that took "vigorous persuasion" and got horrible verticle stringing...

[stubshaft]

If you use moderate loads neck sizing works great without any excessive stretching and thickening.

You headspace a rimmed cartridge just like a rimless one or even a belted cartridge.

[canyon-ghost]

Oh, I should mention I tried shooting some neck-sized cases that took "vigorous persuasion" and got horrible verticle stringing...

Bottleneck cases that headspace off the shoulder sometimes flow forward when fired. I'm generally shooting the tapered cases, 22 hornet, 32-20, etc. Of course, this is one reason I leave the room at the rifling and don't set the bullet right to it.


Also have a 7mmTCU but, it doesn't seem to have that trouble yet. It's a 100% neck sized case from wildcat dies. My guess would be that you'd only full length size when the shoulder moves forward.

The 7mmTCU is one that I have so much brass for that I can't honestly say how many firings it would take to do that.

[Texantothecore]

Break Open actions are quite solid and they go back a very long way to the english sporting arms in large calibers. If your head space is varying you need to send the arm back to the manufacturer for adjustment. These have been around for a very long time and have always performed well with some very taxing rounds, to say the least.

[yovinny]

"Good" break-open or hinged cantilever actions all have sliding bolts and top fasteners.
Features that were found as needed to counter the bending forces on these actions, well over a century ago.

Yesterdays and todays CHEAP versions of these type actions, try to correct a serious design deficiency strictly through the use of a stronger steel, instead of a better (read more expensive) design.

Kind of like a doctor just treating the symptoms, instead of the underlying sickness or problem.

You pay you'r $2. and take you'r chances, but any action of this design is going to have spring to it, especially without needed clamping features.

Just my $.02
Cheers, YV

[leadman]

Most of the single shot guns like the T/Cs and H&Rs have a certain amount of clearance between the end of the barrel and the breech. If there is no clearance this can cause accuracy problems.
so if your barrel has the max amount of headspace and .003" clearance between the barrel & breech you have an excess headspace issue. This is why you fireform the shoulder forward to contact the shoulder in the chamber. you make the case fit the chamber with the clearance.
My Encore 7mm Rem barrel has the max headspace cut in the barrel for the belt plus .004" clearance, the max per T/C. The brass is also short from the belt to the shoulder. If I don't fireform with Unique and COW before loading full pressure loads I may get 3 loads out of a case, more likely only 2. With fireformed brass I have gotten 6 or 7 loads.

If you take a piece of masking tape an put it on the shoulder of a new case the rim may set in the recess in the barrel still. The tape is just filling the extra room. A chamber cast of most production guns is enlightening.

[largom]

If you fireform the cases 2 or 3 times WITHOUT full length resizing you will have next to zero headspace.

Larry

[singleshot]

If you fireform the cases 2 or 3 times WITHOUT full length resizing you will have next to zero headspace.

Larry

So far this has been my experience, but I don't have experience with enough different cartridges and guns to say for sure this is a universal problem with break-opens...thus this thread.

[Hamish]

Two thoughts. The 40 degree shoulder, from everything I have read, is right up there with sliced bread for helping to keep stretching to a minimum.

The trick of seating the bullet/boolit into the lands the first firing to completely fill out the case to the chamber, followed by minimal neck sizing seems to work very well.

I personally do not like to do anything more than is necessary to the case to get it to chamber in the firearm *it's been formed to*.

I am hopeful that at least a couple of the senior members will pipe in for this discussion. Just remember that the Search function will lead you through the looking glass.

[largom]

If you have more than one gun in the same caliber I highly suggest the Stoney Point "Cartridge Headspace Gauge" which is now sold by Hornady. Sold by Midsouth for $35.00 with inserts for most all cartridges.This is a great tool for setting up your full length sizing die if you want to bump the shoulder a thousand or two. Will also show you the difference between a fireformed case and a full length sized case.

Larry

[leadman]

For a break open like the Contender/Encore the feeler gauge works great. IIRC this is what Bellm is using now.
My 30-30AI does not stretch much but it is more critical to have the shoulder in the correct spot. I check the cases in the gun when I start sizing them, then when I think I have it right I put a live primer in a case and fire it. This way I know it will go off with the die setting. Hopefully with my new Lee Classic turret press I can leave the dies installed.
The other cases like the 7 mag, 243 win, etc. are less critical on shoulder placement in the chamber. The 22 K-Hornet is real easy as the brass is much thinner and smaller so closing the action completely is no problem.

[uscra112]

I know my .22 Hornet 'tender was eating brass like popcorn at the movies until I converted it to a K-Hornet. Now I can headspace on the shoulder and brass life seems indefinite.

I'm frankly a bit skeptical that Bellm has accomplished what he says he has. The Contender/Encore design, with the horizontal sliding bolt, was abandoned by shotgun makers in the USA before World War One. It is not at all a strong lockup, since it cannot preload the barrel down into (onto) the table. (For a much better design, look at the old Maynard.) Bellm may have gotten a few very tight groups with carefully set up guns, but will they do that every time? And 1000 or even 100 rounds down the road, will they still do it? I'm doubtful.

Am keeping mine, with a .357 Max barrel for deer, (I'm in Ohio), and the K-Hornet. I'm over my infatuation with the 'tender, and won't be buying any more barrels. (Anybody want a ten inch .30 Herret? Complete with 100+ brass and dies? Make me an offer. . . . .)

[Idaho Sharpshooter]

I have a TCR-83 break open single shot, the DST model. It has a 30-378 Weatherby barrel that came with it. The magnum stamped actions were very strong, and stylish. I only have about 250 rounds thru the Wbee barrel, but a couple thousand thru the 30-06 and 7 Rem Mag barrels.
The 12 gauge barrel only has a couple boxes of goose loads thru it. It hasn't sprung yet, but I have only had it fifteen years.
It hasn't sprung yet...

Rich

[218bee]

Please explain more about Bellm headspace guage and doesnt he make/sell "shims" to help with excessive headspace? I cant picture how that works unless the shims are for the Breech Plug?
LEADMAN so I guess your are adjusting your dies to control the case and measuring with the feeler guages and readjusting your dies?
Maybe its too early for me to grasp how this is working.
Good topic :coffee:

[Texantothecore]

Yovinny, the older guns had metallurgy that was lacking by today's standards. The science has changed so much that it would be almost unrecognizable to a metalurgist from 100 years ago. The older guns had slide locks and top locks because they needed them due to metallurgic concerns and some engineering issues.

I spent 35 years in steel manufacturing and the engineering required to produce a tight break open action is fairly trivial compared to other issues that we handle in the manufacturing sector on a daily basis. Our engineers are the best in the world and this issue is way down the list of difficult things to design.

The most accurate gun I have ever shot is a break open action. Ten rounds in quick succesion through the same hole at 100 yards, .5 MOA using a bullet that is itself nearly .5 moa.

[yovinny]

Yovinny, the older guns had metallurgy that was lacking by today's standards. The science has changed so much that it would be almost unrecognizable to a metalurgist from 100 years ago. The older guns had slide locks and top locks because they needed them due to metallurgic concerns and some engineering issues.

I spent 35 years in steel manufacturing and the engineering required to produce a tight break open action is fairly trivial compared to other issues that we handle in the manufacturing sector on a daily basis. Our engineers are the best in the world and this issue is way down the list of difficult things to design.

The most accurate gun I have ever shot is a break open action. Ten rounds in quick succesion through the same hole at 100 yards, .5 MOA using a bullet that is itself nearly .5 moa.

I don’t want to argue, but no matter what the material, it can’t overcome engineering deficiencies.
If those features weren’t needed, then they would be omitted from all of these type actions being built today, not just the cheap ones.
You find me any top shelf cantilever hinged design, made then or NOW, that doesn’t include those features for locking and I'll eat my hat.

Cheers, YV

[Texantothecore]

Get out the hat, salt and pepper to taste. The Famars Antares does not have a slide locking mechanism. Doesn't need it.

[uscra112]

Please explain more about Bellm headspace guage and doesnt he make/sell "shims" to help with excessive headspace? I cant picture how that works unless the shims are for the Breech Plug?
LEADMAN so I guess your are adjusting your dies to control the case and measuring with the feeler guages and readjusting your dies?
Maybe its too early for me to grasp how this is working.
Good topic :coffee:

Yes, Bellm sells shims to move the firing pin bushing in or out. Downside is you can only optimize one barrel this way. I chose to optimize my .357 Max. since it has no shoulder, and I fireform my .22 K Hornet brass to optimize it.

Bellm has a rigamarole using feeler gages, but I find that I can get a pretty good idea of headspace by firing a primed but unloaded case in the gun. Measure primer protrusion afterwards, and there's your headspace. This may give results that are don't correlate to the feeler method if you use hot primers, and/or you are working with a case that has a shallow taper to the shoulder. (Like the standard Hornet!) I got good correlation doing my K Hornet using Rem 1 1/2 small pistol primers, which are the mildest you can buy.

[uscra112]

Get out the hat, salt and pepper to taste. The Famars Antares does not have a slide locking mechanism. Doesn't need it.

According to their website, the Antares does not have a TOP locking bolt, like every double gun made since before WW1. It has ONLY a slide bolt to lock it. (Lacking drawings, I assume it's below the barrel axis.) It also releases with a hefty lever, which suggests that it either has a much stronger spring to engage it, and/or the lever is used. They also claim that the sliding bolt is very large.

The T/C is a neat gun for cartridges up to something in the neighbourhood of .357 Magnum, or maybe even .30-30. Putting 60,000 psi cartridges like the .243 in that frame seems about as useful as a 427 in a Pinto chassis. Sure, you can do it, but what have you got when you're done? And how long will that chassis last?

[leadman]

I probably have at least 2,000 rounds thru my 6.5TCU barrel alone. That is on one Contender frame that has probably seen 15 or more barrels on it besides the 6.5.
My Encore was bought in 2006 with a 28" 7mm Rem Mag barrel on it. I don't know the exact round count on it but I shot several powders thru it before settling on IMR 7828. The new #8 container I bought is almost gone. It still will consistently shoot less than 2" all the time at 200 yards, and if I'm having a good day it will go down to an inch. This is no wimp load either, 150gr Nosler BT at 3,300 fps.
This frame has also shot loads from 4 other barrels with the 6PPC probably adding 500 or so more shots. This barrel is usually a 1/2moa shooter.
I have a Contender carbine 223Rem on an older frame that shoots between .3" and .5" with bulk Hornady 55gr bullets.

These guns just keep on going with few problems. I did break a locking lug on the Encore but it was an easy and no cost fix.

The Bellm headspace gauge mounts a dial indicator with the base of the gauge mount setting on the end of the barrel. The dial indicator is used to measure how far the brass sets out of the barrel, and sometimes below the end of the barrel. This figure is used with the gap between the end of the barrel and the breech face. If you have too much clearance, or headspace as it is normally called, then you can put a shim on the backside of the removable breech block that contains the firing pin. But as said this is only good unless you are lucky for that particular barrel.

It is easier to match the brass for each barrel to the existing dimensions when mounted to a particular frame. This pretty much the same as what I am many others do with the old mil-surp rifles that are out of spec on headspace.
Headspace is the amount of clearance between the chamber and the brass measured the length of the brass or chamber. Anything over .006" is considered excessive. But when you fireform the brass to the chamber you usually close this figure up to about .0015" to .002" depending on how much the brass springsback after firing. As long as you set your dies so the shoulder is not pushed back too far you have the correct amount of headspace.

[yovinny]

Get out the hat, salt and pepper to taste. The Famars Antares does not have a slide locking mechanism. Doesn't need it.

Sorry brother, it sure does have a sliding lock, that they stress is 3X bigger than comparable rifles.
It seems to appear it doesn’t have a top fastener though.

I'm not that familiar with them, but they seem to tout that the bore centerline is minimal distance to the hinge, minimizing the cantilever distance and radial force on the action.
This would mean they also made an engineering change to improve the design, rather than just a material change.

If you could design a hinge action with the hinge at exactly center bore, like an old time cannons pintal hinge, than you'd eliminate all the radial force and you'd really have something. Something almost as well designed as a bolt action or falling block ;-)

Cheers, YV

[yovinny]

T/C is a neat gun for cartridges up to something in the neighbourhood of .357 Magnum, or maybe even .30-30. Putting 60,000 psi cartridges like the .243 in that frame seems about as useful as a 427 in a Pinto chassis. Sure, you can do it, but what have you got when you're done? And how long will that chassis last?

+1,, Cheers Bro :D

I actually know an armor company that uses the T/C frame for their test guns, instead of a universal reciever.
They claim that between the cost of barrels and replacing damaged recievers, their still ahead money wise, instead of the universal reciever and having barrels custom chambered and threaded.
Their known to push some very high pressures, but they do it remotely in a sealed room and toss more than a few actions a year.

[EDG]

The length and area of the components under load determine how springy the action is. The modulus of of elasticity of most steels is similar so they will all stretch the same under the same load. Some just take a higher load to permanently deform.
On the other hand the 3200 Remington and those that lock up in the same fashion will take high loads. I am not talking about the top lock but rather the load carrying side lugs on the monoblock.

The 3200 will take a lot of pressure without stretching. The top lock only Valmet not so much.

you can see a 3200 Remington open here. Note the side lugs that take the load off of the hing pin when the gun is locked.

http://www.micksguns.com/images/remington3200-2.jpg

[Texantothecore]

Well, I stand corrected on the Antares, but with the continuing reputations of Contender and H&R, which are very good, I still contend that engineering in them is quite good and adequate to the task.

Any springiness in one of the these actions would result in varying headspace which would be detectable by bullet dispersion at the target. It isn't there. Both lines of rifles are well known for the accuracy. My Buffalo Classic is quite accurate.

[TXGunNut]

All my life I have heard and preached the gospel that break open rifles are springy and cannot be made accurate.

I can now witness to the fact that Thompson Center Arms has put that opinion to rest. I can see no difference in accuracy between my high walls and my TCs. Either will easily do sub-MOA.

That said, the bolt still beats them both handily. -williamwaco

I've never owned a break-open rifle but I've had Contender pistols for 20+ years that would (and still do!) outperform almost every rifle I own, including bolt guns. Like my friend from Deary case life was excellent in .35 Rem as well. It may be a weak design compared to a bolt gun but apparently the folks @ T/C know how to get the best from it.

[Te Hopo]

Hmmm I have one of the Baikal IZH18's (Remington SPR18) in .270 and find it to work great, 3 years on I am still reloading the original Federal Premium brass that I got with it
Must be onto it's 15 or 20th loading and still no signs of case head separation.

Mind you my handloads are at the low end of the spectrum, just the standard old Lee Loader scoop of H4350 and a 130g bullet.

[Crusty Deary Ol'Coot]

Yes, I realize that there are bad chambers and bad sizing dies, but as per the last two posts, and back to my ealier post, custom adjusting your full length sizing dies to YOUR chamber goes miles and miles towards proper cartridge fit and Looooong brass life.

As said before, Always size brass fired in your chamber the minimum amount needed to allow that brass to smoothly rechamber in YOUR chamber.

That doesn't mean brass sized in a properly adjusted full length sizing die - set up for YOUR chamber - will chamber in another fire arm of the came caliber, yours or someone elses!!!!!!!!.

Keep em coming!

Crusty Deary Ol'Coot