bfrshooter: My experience with pistols and rifles is that cast bullets yield much higher velocity with equivalent powder versus jacketed. As far as pressure is concerned, seems like a simple excercise with Quickload or equivalent. Since I'm usually loading for a particular velocity, I reduce the amount of powder with cast to achieve the same velocity.

Here we go...Ladies and Gentlemen..Round 2

OK, forgive me for bringing that subject up. Its not what I'm really interested in anyway.

How can I really measure my bore? Slugging only reveals the tightest spot. How do I find the widest spot?

use a inside mic this is what is used for aircraft maintenance.
pete

BFR, That's exactly the debate that raged on the ol' shooter's board about a year ago. There's conflicting information all around us. I can pick up a Midway LoadMap for, say 9MM and find more pressure with cast bullets of identical weight & powder charge than with jackets. On the flip side, my experience with .44 mag is similar to yours.....a 429421 will not flatten a primer with 25g H110 but a Speer SJSP of equal weight will. I seem to recall that folks were talking about pressure spikes and how a cast bullet will enter a pistol throat quicker than a jacketed bullet and thus providing the burning powder more room in the case and yada yada. There were a dozen hypotheses offered and rebutted.

My conclusion (likely worthless 'cuz I have far less direct knowledge of the issue than evverbody else here) is that every load seems to have a personality different from the next.....which in itself doesn't make sense from a physics standpoint. Gotta admit though it's a great topic.

dla
Was just wondering if you called Marlin?

Joe

bfrshooter,

You made me think about something. I would love to see a barrel wear comparison between to identical barrels in same calibers one shooting jacketed bullets and the other shooting cast bullets. Let's say 308 Winchester with 150 gr bullets. Here's the rub though, I want to see the velocity of both at say 1500 fps.

You are right about 22 rimfirings not wearing barrels much but you're also looking at a pressure noways near centerfire rounds, alot less powder, and alot less heat. How many of you have heated a 22 rimfire barrel up too hot to touch from shooting? Machine guns not included. One more thing on 22 rimfires...alot of the bullets for them today are copper coated. They don't seem to wear the barrels out either. I've recovered copper plated bullets fired through a 22 undamaged and examined them and they didn't show that the rifling cut through the copper into the soft lead underneath. So what I'm saying is copper plated 22's are copper against the steel going down the bore. How many of you have ever seen a 22 rimfire magnum barrel shot out? Now most the bullets for that round are jacketed, except CCI's which are plated. Explain why 22 magnums don't wear barrels out. A step further, shoot the same 40 gr jackets bullets used in 22 magnums in a hot loaded 22-250 and tell me which one will wear the barrel out faster. Do you think maybe pressure, velocity, and heat does have alot to play with barrel wear?

Joe

I missed that discussion on Shooters. But one obvious difference i haven't seen mentioned is that lead bullets (and copper plated .22 rimfire bullets) are nearly always lubricated somehow or other, whereas jacketed bullets almost never are.

starmetal: No I haven't called Marlin. Why? Multiple reasons:

(1) My rifle has over 1000rnds through it

(2) Is .457" out of spec?

(3) Every Marlin on the face of this Earth has tight spots in the same locations. If this really bothered Marlin, they would've fixed this 20years ago.

(4) It shoots jacketed just fine.

"I know the chamber of a Marlin, my Marlin, is not very tight. And it is very difficult to seat .460" bullets straight without "the bulge". I wonder if a different seating die/ neck expander would help?"

Brings to mind another item loading for these straight walled 45/70's. Often the seating stem isn't real compatible with those flat nosed slugs and allows off center seating. Solution is partial sizing to get just enough good grip, clean the case neck inside with an old brush prowered, just enough flare for easy bullet entracne and DON'T start the bullet into the case before inserting into the die body. Let contact with the stem at ram raising start this process with a deft touch seating. Better uniformity.

Are you cleaning the jacket fouling otta the bore before shooten cast??

Aladin
I wouldn't exactly call Marlin's a cheap gun. I don't mean that in the sense of quality but price.
Unless someone has a pretty damn good job and keeping his house running, taking care of the wife and kids, I can't see how a Marlin would be cheap. Maybe compared to a Kimber, or SAKO, or such, but certainly not cheap. Cheap to me would be a H&R single shot.

I can see how stamping the nomenclature can cause a tight spot because it's actually displacing metal that has to go somewhere and that somewhere's is in the bore constriction. But how in the devil does milling a dovetail slot in from the side of the barrel make a tight spot unless it's when the piece that the dovetail is for is slid in?

Aladin do you know the margins they take to make their "cheap" guns for fact?

Joe

I wonder if some of the anomalies seen with pressures and velocities between cast and hardshell bullets isn't partly a function of the alloys used. Copper on steel is so-so as a bearing material; copper plus tin (= bronze) is good. Pure lead is "sticky" (we are told), but some of our harder alloys are in the (very broad!) Babbitt range and are VERY "slick". And then there are the frictional properties of the various barrel steels (e.g. some stainlesses are very "sticky"). No wonder there is a lot of variation in results! (Not even including lubed vs. un-lubed.) floodgate

dla, I've a suggestion (and I haven't tried this). You know where those constrictions are. Same place they all are. For starters, measure you're push rod to the first one from the chamber end and from the muzzle end. Then shove yer slug just far enough to not quite hit the constriction and them shove 'er back out and get your mic out. You'll know what the two ends are and the middle is prob'ly somewhere in between. Regards, Woody

dla you have a PM.

starmetal: I don't believe they mill the dovetails, instead they stamp them. I'm not sure, but I believe it is called "broach cut".

dla,

Just an interesting story. Layne Simpson, I believe he writes for the Shooting Times rag, has a strong liking for the Marlins. He wanted to see just how accurate one could be in the 30=30 chambering so called Marlin to ask them about their barrel making procedure for the 336 model and about his project. They said the barrel is a heavy straight blank first and they turn it down to the dimensions to fit the 336. He said he would like a rifle with that barrel unturned. They replied that it wouldn't have a forearm and magazine tube on it if they did. He said fine that he would take it that way. To shorten the story he got it and got it to shoot 1/2 inch ragged holes at 100 yds. He was out to find out the truth that leveraction rifles can't be as accurate as bolt actions.

I think it's a shame for Marlin to ruin their barrels by whatever procedure they are cutting those dovetails by. They also might take a look at some of the other manufacturers who have eliminated the stamping of the nomenclature on firearms and going to laser engraving.

Joe

It's just a miracle these lever guns shoot just good enough to have a little fun with. Anything better than an inch would be pure luck, and to save disappointment, these guns of mine are never "sighted in" for grouping, and never on paper (ouch!), just only on charging beer cans in the heat of battle. ... felix

dla..For the record, a broach is a tool used to remove metal that has multiple teeth, each one a little deeper so the metal is removed in one pass. It similiar to a mill in that it removes the stock, but it is a cheaper method. In short a broach removes the metal like a mill and does not displace it like a stamp.

dla..I pull my Marlin 1895SS out of the safe and took a good look at the dovetail under magnification and a strong light. There is no question that the dovetail was cut and not stamped. There are plenty of tool marks in the bottom of the barrel. The dovtail was cut with a broach as the tool marks are straight accross and not in a swirl pattern produced by a mill. I can say with 100 percent certaintyh that the dovetail on mine was not stamped, but cut with a broach. A broach cut may not be as precise as a mill cut but should not cause obstructions in the barrel.

22 barrels and military barrels (03, 03A3,Grand and others)have been rifled with a broach for many years. These barrels shoot very well when compared to barrels cut with multiple passes of the cutting tool.

There is nothing wrong, inferior or cheap in the way Marlin cuts these dovetails. Any method used in mass producing barrels will produce some duds and sometimes these duds get by the inspection process.

Chargar : Thanks for the education on broach cutting. I too looked at the dovetails on my Marlin and I can see the straight line tool marks. I had assumed that they were "Stamped" in interest of speed.

Although I understand your point that broach cutting in itself shouldn't deform the barrel, I've slugged two Marlins (45-70 and 30-30) and they both had the restrictions at dovetails and nomenclature.

"22 barrels and military barrels (03, 03A3,Grand and others)have been rifled with a broach for many years. These barrels shoot very well when compared to barrels cut with multiple passes of the cutting tool"

'Bout fell off my chair Charles when I read that. Ever hear of a fella named Pope or maybe Obermeiyer or say Rock or Krieger? All single point cut and they all shooten as good as anything anywhere.

In reality rifling a barrel still depends on the skill and care of the man doing the work and what care he takes with his tooling. All methods can produce top end barrels, some are just associated with inferior quality via mass productions standards.

Marlin tubes are button rifled BTW. The Marlin 30 caliber blank I have is very uniform end to end albeit it measures 3032 by 3085. And the muzzle hole is off center by around .020" which isn't necessarily eliminating it from being chambered. Just put if off as I lost interest in a 30 BR...

Aladin..Yep..the name of Harry Pope and others like Axel Peterson and Wm. Schoyen and other master barrel makers of yor, seem to jingle a bell. There are also some contemporary master barrel makers. We are talking of hand made, hand lapped barrels. I was comparing mass produced barrels that are broached rifled to mass produced barrels produced in the convential way. This is an apples to apples comparison. To compare a mass produced broach rifled barrel to a Pope barrel is not only a apples to oranges comparison, but also a little silly. I thought folks would understand that. Forgive me if I over estimated the ability to read and understand with a degree of dicernment.

Nope Charles ya tried to wiggle away from what you said. The quote gets to the point.

No matter, just a friendly poke. The old masters still rifled on a lathe of sorts I think. The hand work was the lapping and sometimes tapering down to a smaller diameter at the muzzle. Seem to remember their steel was much softer too. Maybe someone with more knowledge on that can comment.

[ 11-09-2003, 06:13: Message edited by: aladin ]

Aladin..Really wasn't trying to wriggle. The trouble with the net is that we are a diverse bunch and do not share the same vocabulary. Posting where you need to define each terms becomes to complex to be fun.

In my momenclature the term "handmade barrel" is used to distinguish a barrel made one at a time, vs. those made by automated machines. All barrels use some sort of jig to index the stock, be that a centuries old wooden jig or a Pratt and Whitney barrel making lathe. All I was trying to say is that in the world of automated mass produced, broached rifled barrels held their own.

Broach rifled, button rifled and hamer forged barrels can all be "good" barrels. But the "best" barrels are still made one at a time pass by pass with a cutting tool in the grooves. Stress releaved blanks are a big help and the best of the best require no straightning and little lapping.

Truly fine barrels are still works of art by master craftsmen, but they they were in the days of Harry Pope.