Burnside - a new solution ?

[johnsymborski]

I posted a couple of times on Burnside topics, and have thought of a novel approach to use conical rounds (.556 diameter are typically available to fit either the brass or nylon cases sold today). These rounds don't fill the full depth of original rifling (.560), so thats why they don't group very well. Up to now I've been modifying brass cases to accept .562 rounds (round or conical) AND soldering a .030 #8 brass washer to the base so the case will chamber properly and not move rearward when firing (which causes case failure). The nylon cases are long enough, but stretch when a full-diameter round is inserted and will not chamber. A proposed solution ?

Have the Burnside re-lined to a .540 nominal bore with .075 deep rifling at 1:60 twist WITHOUT gain twist. That will yield a bottom-of-groove max diameter of .555 - and so a .556 conical round (like many Burnside molds make, as well as the size on pre-packaged alloy Burnside rounds) will be perfect for the bore AND will fit into either the brass or nylon cases available today. There is still the length issue on brass cases, because they can vary considerably as supplied, but nylon cases appear to have only one source and are long enough.

Of course, one can argue that you are no longer shooting a 'real' Burnside. Hmmmm, I'm still working on getting my Burnside to shoot well as manufactured, and have put too much work into modifying my brass cases to consider a re-line. With .562 round ball (37.5 grains 3F) I can get all in the black at 50 yards. It will take additional mold modifications to see if I can get the right conical round length (thus weight also) to work at 50 AND 100 yards. I'm milling off the aluminum mold from Accurate (I started with the longest round offered, and even then had to touch-up grind the base rings with a variable speed 'dremel' to get .562 diameter instead of the .560 that would originally come out of the mold.) a little at a time to slowly bring the length down to see if I can get the group to tighten at some point. The brass case mouth can be hand-reamed with a .562 reamer with care. My adjustable reamer had to have the front adjustment nut ground around the periphery so that it would fit inside the tapered portion of the brass case. A single-purpose reamer (as available form industrial suppliers like MSC) won't have this challenge, but a tap handle is still used to accomplish hand reaming.

[Carolina Reb]

One thing I have discovered about Burnsides, if you want to shot conicals, they like heavy bullets. The ~360 grain ?Burnside? molds are simply too light to shoot well, and the narrow grease grooves don?t hold enough lube. The old Dixie hair curler mold was a pain in the butt, but those bullets were 400+ grains and shot well. I was the high scorer on our carbine team more that once with the old Dixie bullet.


Since then, I have gone through two more Burnsides, and a lot of Burnside molds, mostly homemade, with weights up to 450 grains. I?ve settled on the 0.560? diameter Accurate 56-390A cast in pure lead. I designed this bullet with a single wide grease groove, like some originals, and used the original elliptical nose profile, rather than a constant radius curve. Once compromise is the nose flat, which is required by the mold maker.


If you have a tight bore, these can be sized to 0.556?, but my current Burnside isn?t tight. I made a neck expander for the brass cases to open them out to 0.560?. Cases have to be annealed to expand the necks. Lead pot annealing works best. In order to consistently expand case necks, I ended up making a set of loading tools inspired by the old Harmon Maynard loader. The nice thing about using loading tools is that bullets are always seated square in the case and crimped in place.


The cases Lodgewood was selling 5 years ago fit my chamber perfectly, but they did need the bases reworked a little to better fit the plunger face. The ones from 35 years ago were too short and had the sealing ring in the wrong place. They would blow out the necks with anything over about 25 grains of FFF. I haven?t needed cases in a while, so can?t comment on the current ones.


If some sutler would like to make Burnside loaders, I?d be glad to supply drawings and pictures.

[Joe Plakis, 9575V]

Or you could give Accurate Molds a try..... They have five burnside bullets listed on page 24 of their catalog.... Now I have never used their bullet for a burnside, because I don't own one..... But I do currently own a few of their molds and they are of superior quality...

http://www.accuratemolds.com/catalog.php?page=24

[Carolina Reb]

Actually, in my quest for an accurate Burnside bullet, I designed 3 of those molds at Accurate Molds. The 56-450 shoots well, but it is too long for most 5th models. You have to take the breechblock guide screw out in order for the breech to open far enough to chamber it. My current carbine is a 4th model without the guide screw, so I didn't know it was a problem until somebody else tried the mold. The 56-390A is the best all around conical I have found. It is essentially the original bullet with a nose flat.

[noonanda]

Actually, in my quest for an accurate Burnside bullet, I designed 3 of those molds at Accurate Molds. The 56-450 shoots well, but it is too long for most 5th models. You have to take the breechblock guide screw out in order for the breech to open far enough to chamber it. My current carbine is a 4th model without the guide screw, so I didn't know it was a problem until somebody else tried the mold. The 56-390A is the best all around conical I have found. It is essentially the original bullet with a nose flat.

Ive got the Accurate 56-350B have only tried it a few times but plan in working with it to hopefully get a accurate load

[johnsymborski]

Yeah, the Accurate 450 (mine cast at 435 grains) was too long. Milling some off the back of the mould helped as far as working the action with the guide screw still in place was concerned, but the rifling in the bore contacted the area of the round ahead of the lead grease groove when chambering - and that made full closure of the action troublesome. (I increased the diameter around all the grease grooves to .562 previously.) Using a 2-step sizing procedure to reduce the diameter a little ahead of only the 1st grease groove made chambering OK, but I wasn't able to match the accuracy with any powder/grain weight combination - compared to the group size of a round ball load (and the round ball is quite light - something like 250 grains). This makes me think that its not just the round weight, but the 'fit' and aerodynamics that have to be 'right' to work with the Burnside gain twist. The grain weight of my modified conical is 417. I'm using tin-lead for these rounds, but perhaps should try pure lead for the conicals. I'll try milling off a little more to tweak the weight (and aerodynamics a little).

[Hal]

Surprising how different they are gun to gun. My 5th model will feed the 56-450B just fine, even with the screw in place. It will not open back up with a loaded round unless you manually pull the breech block back against the spring pressure, which is not hard to do and the need doesn't arise often unless you are doing a carbine team match and you are loaded when time is called.

I just can't get anything to shoot accurately in mine. I'll get a load that gives good results one time and the exact same load will fly all over the place the next time I try it. Round balls included. It needs a bigger bullet, but I can't get one in my cases. I may try reaming them like someone mentioned on here the other day, but I'll have to wait on that.

Has anyone tried a true Minie in one? Not just a shallow cavity in the base, but a true Minie so it can expand larger upon exiting the case?

[ms3635v]

Just a few items of interest with regard to the Burnside. I have a teammate who has been shooting a Burnside for a long time. Initially he was using a .560" round ball, then Rapine Moulds introduced a conical style bullet that resembled in appearance. So, my teammate bought a mould to try in his Burnside. The bullet did not perform as well as he had hoped so he went back to the round ball. The problem with the Rapine bullet was that the diameter was .556", which is too small. I have an original Burnside bullet that was modern cast from an original mould. The bullet cast from this original mould is .564" in diameter and is .790" long. I noted that you were thinking about having the barrel relined, but remember if you do it can only be relined to a +/- 1 caliber in diameter. As for the cases, my teammate uses the nylon cases which perform very well for him. Early on he was using brass cases but with the cost he switched to the nylon. Anyway, just a few things to think about with the Burnside.

[johnsymborski]

Very interesting. I quite forgot that most original Burnside rounds have spun copper cases that were for one use only. The originals did not have the 'ledge' inside for the round to seat on (which the repo cases - brass or nylon - have), so a longer bullet could be accommodated inside without affecting chambering (or removal of an unfired round). I may try to procure an original example for 'forensic' analysis (meaning careful disassembly) to examine the particulars of the components. I suppose, although expensive ($30 to $50 a piece), it would be possible to buy enough enough original cases to reload ... now I'm not serious (or crazy enough) to undertake such a thing. But the brass cases could have the 'seat' deepened with an end-cutting reamer. My guess is that a round cast from an original Burnside mould of aprox. .564 diameter x .790 long would weight about 450 grains. I've posted on another thread that I've hand-reamed brass cases with a .562 reamer (the cases seem to measure .561 after the process). This is a slow process that leaves a mere .010 thick end flange that is prone to denting if dropped, and I sand the lead edge to avoid accidental cuts from such a thin cross section. The cases must all be 1.870 - 1.880 in overall length to assure full chambering and to support the thin lead flange. The cases are all annealed before use so that any loose-fit in the tapered section of the case will be 'fire formed'. I solder .030 #8 brass washers to the base to get the right case length (at least for my Model 5), and can touch up if needed with a file. This means that when being cases I check that the OAL is at least 1.840 ... there are many that are under that - as low as low as 1.810 - and those are rejected. I make sure to wash the brass (hot soapy water) soon after firing to avoid any corrosion, and do a dip in white vinegar (then a water rinse) as a precaution. The results with .562 round ball are consistent sat 50 yards, so its the 'hunt' for a conical that will work at 50 or 100 yards that I'm on now.

[Carolina Reb]

Here are some more thoughts on shooting Burnsides.

According to Roundball to Rimfire, Vol. 2, most Burnside bullets are 0.561-2? in diameter, 0.79? long and around 385 grains weight.

The lockup on a lot of them is loose. With a case in the chamber and the breech closed, there shouldn?t be any up and down movement of the lever, and definitely no clicking sounds. My first one was that way, but not the second or third. My current Burnside required a 0.005? shim under the J hook screw at the front of the trigger plate to get it to come tight at the correct orientation. It also required a 0.005? shim in the latch to take up the lockup slack. These fixes helped accuracy quite a bit.

The lever to breechblock screws on some carbines tend to come loose. When they do, accuracy suffers.

For the brass cases, hot lead anneal the case necks to behind the ring. This will allow them to expand and fit your chamber without splitting the case mouth. On my carbine, they grew from an ID of 0.558? to 0.561? in just a couple shots, and they have stabilized there. No reaming necessary.


The reason the Burnside is my backup is because the stock fit makes it hard to lock in with a tight hold. Smiths are better, and Merrills are way better in that regard. And, the Burnside seems particularly sensitive to not using a tight, repeatable hold. When I shot the Burnside all the time, I hit a lot more with it.

Took the old General out to the range today and shot 3 holes touching at 50 yards, then the heat started to get to me. Heat index here is well north of 100, with very high humidity. It doesn?t take long for me to start shooting big groups when it?s like this.

So, why do we keep screwing with these things? Because they are a lot of fun to shoot!

[geezmo]

CR,


Is that with the .560" 56-390A mold that you spoke of above?

[Carolina Reb]

That's the one, cast with musket lead.

[noonanda]

That's the one, cast with musket lead.

Have you tried them using harder lead, and if so how did they shoot?

[Carolina Reb]

I tried 1 part WW and 2 parts pure lead in my good load, and it did not shoot as well. In fact, groups opened up to about twice the usual size. I have not gotten systematic to see if there is another load that works as well as soft lead.

[johnsymborski]

My Burnside has been on the shelf a couple years, but the article in the latest Skirmish Line on adjusting a Burnside got me to pick it up again. Now I already put a brass shim under where the sear rests at full cock ( and that is tricky to do on a Burnside), so the trigger pull is acceptable, but might use just a little polishing. NOW I see where 150 years of drying have changed the rear stock dimension just enough to cause lateral play - known as 'yaw' (roll, pitch and yaw being three freedoms of motion, like on an aircraft).

So instead of 'bedding' (which I generally don't like to do), I fashioned a tapered shim to fit on the left side of the rear stock where it meets the receiver. BTW, Burnsides were marked just about everywhere, and on the inside left front of the rear stock are the last 4 digits of the serial number seen elsewhere - so all the parts are original to the firearm. After enough test fittings, when all the screws are tightened up (done a little on each one in sequence until all are tight), the connection between the front and back of the gun became 'rock solid'. Note that the tapered shim gives the butt stock the slightest 'offset' ... something that many PA long rifles were made with, and is something that helps the 'fit' to my body and shooting style better. The J hook was shimmed to be both tight and correctly aligned.

Incidentally, my 'put together' Smith had a bit of 'yaw' due to wear in center of the knuckle joint (and the mis-matched front and back did not meet squarely ... my guess is that during manufacture, mating halves were drilled and 'line reamed' together in a jig). Using JB Weld to form a tapered 'gasket' (saran wrap prevented sticking to the front during curing) the gun was snapped shut with the lock oriented down and then rested on a support of the lock. This created the slightest bit of aforementioned 'off set', eliminated 'yaw' (once cured) as well as stopping gas leakage. Before this treatment, the rounds had too much windage (caused by the 'yaw' between the front and back halves of the carbine), and I was chasing my tail trying to knock the rear sight to one side or the other to correct. With a solid relationship between the front and the back, the shot group was tight and stable enough to medal in individuals and team competition. After enough use, the JB weld 'gasket' can blow out ... but is easy to re-do after degreasing.

An empty chamber still wiggles slightly characteristic of Burnsides), but my modified cartridges eliminate all or nearly all motion (the labor intensive steps are noted earlier in this thread). Soooooo, from reading many of the posts on Burnside rounds in this and other forums - it seems that SOFT lead may be an additional requirement for getting a decent group. After all, the original rounds were of soft lead - and soft lead will obturate better, versus the 'swaging' that occurs with harder carbine leads. And i NEVER considered trying soft lead before ... duh.

As said, the .562 roundball (hard lead) works fine at 50 yard, but I wonder what the result will be with SOFT lead round ball. Time to get back to a practice range.