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- Hillbilly shack in the boonies
Boattail or spitzer.? And why? 
Also advantages of both?
Also advantages of both?
What base bullet do you think will burn out a bore quicker?
- Thread starter Levi Garrett
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Finger Toes
Regular
- Location
- Yellowhead County
Do you mean boat tail or flat base?
Finger Toes
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- Location
- Yellowhead County
I'm sure a barrel maker would tell you that jacketed 100 grain bullets wash out the rifling quicker than 75 grainers in say a 243 or 6 BR. The length of the shank or the part that engraves into the rifling plays a part in barrel wear. Remember lead bullets are notoriously easy on barrels, it's more than just pressure and temp. Theoretically a boat tail would wear less over time than a flat base of the same weight because of its shorter shank. The difference might be almost imperceptible though and I wouldn't stop using flat base bullets for fear of burning out a barrel quicker. I have once read about boat tails eroding the crown quicker but that takes to long to explain and I haven't heard anyone complain of since.
OK, I would like to challenge a couple of these statements. First "Ball powders burn hotter". In actual fact, ball powders were specifically developed to assist in extending military barrels 's life, due to slightly cooler burning characteristics.
Secondly, that bullet shank length has anything to do with barrel life is a stretch, at best. Bullets do not wear barrels any appreciable amount. Heat and superheated gases erode barrel steel, particularly near the throat. The reason that lead bullets do not wear barrels out as fast is that almost always, powder charges for lead bullets are smaller, and thus the heat generated is less. It was thought at one time that boattail bullets were harder on barrels since the area between the boattail and the barrel would "funnel" hot gases to the barrel steel, cutting it faster. This theory has been pretty well laid to rest now. I would be willing to lay a fair sum in a bet that the difference between FB & BT bullets is negligible. Barrel makers will unanimously agree that heavier powder charges are the culprit in reducing barrel life, regardless of the bullet of choice. [Note the difference in barrel life between a 7-08 and a 7mm RUM.] Regards, Eagleye.
Finger Toes
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- Yellowhead County
What about the fact that steel jacketed bullets wear out barrels quicker than copper jacks?
Fact? Says who? Heck of a difference in the malleability and hardness of a bullet jacket and that of a modern rifle bore, and where in the hunting world would it make any difference anyway? The "overbore" term, big powder capacity for diameter cases leads to throat wear long before a barrel will be affected. But back to the original question, Eagleye put it right - there's little evidence to support bullet style making any appreciable difference in bore wear.
- Location
- Vancouver Island BC
Again, another reality check from Eagleye. I don't have anything to add to that......amazingly.
A large charge of powder blasts burning powder down the barrel throat and the powder is physically erosive.
Flame temperture might be the single most important factor in throat erosion (the part of the barrel that burns out). I have seen differences over 1000 degrees C. It has been my observations that in rifle powders, the ball powders are much hotter that the single base powers. Ball are "double base". I assume it is the nitroglycerine that makes them hotter.
Handloaders might find this link interesting.
http://www.geometrotec.com/information/info/ballistics.pdf
Flame temperture might be the single most important factor in throat erosion (the part of the barrel that burns out). I have seen differences over 1000 degrees C. It has been my observations that in rifle powders, the ball powders are much hotter that the single base powers. Ball are "double base". I assume it is the nitroglycerine that makes them hotter.
Handloaders might find this link interesting.
http://www.geometrotec.com/information/info/ballistics.pdf
To Quote sbtennex: "Fact? Says who?" "Steel Jacketed" is somewhat of a misnomer anyway. In fact, very few bullets actually have a steel "jacket". AP ammo has a very hard steel "core", but that is wrapped with a relatively soft alloy jacket that is actually engraved by the rifling, so not a problem with bore wear. Practically all FMJ military bullets have copper alloy jackets that are no harder to engrave than are garden variety hunting bullets. Norma of Sweden actually marketed hunting ammo [softpoint] that did not use a copper alloy jacket, but in fact was mild steel that was softened for the purpose. I still have some of these bullets in 6.5mm and 270. They worked just like copper alloy bullets, and there is no evidence that they were any harder on barrels than the other types. The only bullet jacket material that was apparently a problem was the long obsolete cupro-nickle alloy used in some military projectiles. This problem was not barrel wear, but rather, metal fouling that was particularly nasty to remove from the bore. Bullets are not the enemy of barrel steel, period! Regards, Eagleye.
Ganderite. I have read this information before. A lot of "ball" powders are indeed double-based. But some are not, so to dogmatically say "ball powders are double based" is technically an error. Conversely, some extruded powders are also double based, while many are not. I would be interested in knowing how you "observe" that ball powders are "hotter" than single based powders, and specifically, which powders you have observed this phenomenon with. It has been established that only double-based powders with Nitro-glycerine levels above a certain level are actually more erosive than single based powders. An example is the older Cordite powders, with a N-G level of 25% or slightly more. None of today's canister grade powders reach that level, whether ball type or extruded [or flake] Regards, Eagleye.
Oh, I know about Ganderite's background.
I'm just curious to see how this observation is made, since at our humble level, we would be unable to tell the difference between any powder formulation in the field or at the range as to heat that is produced. Eagleye.
Finger Toes
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- Yellowhead County
Hey I'm up for learning. But before you all start freaking out why don't you call Sierra bullets and ask for Kevin Thomas. He shoots 50-70,000 loads a year for Sierra and maybe he can convince you that certain bullets wear out barrels quicker than others. Why take it from me? Go to the real horses mouth. One example he'll likely give you is a 107 grain bullet in a fast twist 243 with a 1000 round life expectancy. If copper jacketed bullets don't cause any barrel, wear I'd never get a rope burn. Hope this continues as an enlightening debate and not a Brew Ha Ha. I joined you Nutz for this kind of discussion so lets keep it friendly. If I'm wrong I'll admit it but you gotta prove it first.........Oh wait was this about boat tails or somthin?
I have worn multiple hats over my shooting career. At one point in time I was concerned at burning through more than one barrel a year in a particular rifle (a 300 Win Mag target rifle shooting 200 gr Sierras). I was loading it with 4350.
While doing some work with a powder company, I was reviewing powder data sheets and doing some tests (closed bomb tests) on some experimental powders (using moly as a powder lubricant instead of graphite).
I needed a temperature reference point, since we were most interested in comparitave temps, rather than absolute numbers, so I used 4350 as the base temperature. Our test powders were all quite a bit cooler. I got exceited, thinking we were onto something (using moly was my idea). Then I tested some "standard" powders and found that the other single bases powders were similar temperatures and the ball powers were all much hotter.
The ball powdes were military powders for 5.56 and 7.62. We were trying to develop a new military powder. Two were Winchester and I think one was French.
If there is single base ball powder, that is news to me. I had assumed it was all double or triple base. My observation of ball powders being hot relates to reading the powder files for double base ball powders.
In the propellant businses, low flame temperature is the holy grail. The military is most concerned because the machine guns and canons burn out barrels quickly.
While doing some work with a powder company, I was reviewing powder data sheets and doing some tests (closed bomb tests) on some experimental powders (using moly as a powder lubricant instead of graphite).
I needed a temperature reference point, since we were most interested in comparitave temps, rather than absolute numbers, so I used 4350 as the base temperature. Our test powders were all quite a bit cooler. I got exceited, thinking we were onto something (using moly was my idea). Then I tested some "standard" powders and found that the other single bases powders were similar temperatures and the ball powers were all much hotter.
The ball powdes were military powders for 5.56 and 7.62. We were trying to develop a new military powder. Two were Winchester and I think one was French.
If there is single base ball powder, that is news to me. I had assumed it was all double or triple base. My observation of ball powders being hot relates to reading the powder files for double base ball powders.
In the propellant businses, low flame temperature is the holy grail. The military is most concerned because the machine guns and canons burn out barrels quickly.
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No offense taken or intended!
But if that 107 grainer was a flatbase, would it wear the barrel faster? or slower? The real reason that the 107 in a slow twist 243 [I shoot that bullet in a slow twist 6mm, BTW] is so tough on barrels, is that it is always chased by a fairly stiff charge of slow burning powder. This is the recipe for short barrel life, regardless of the powder type used or the bullet design, and Kevin knows that too. You'll note that I did not say that bullets do not wear rifle barrels. What I did say was that the wear from bullets is insignificant in comparison to the damage done to a barrel by the hot flame of the burning powder. Regards, Eagleye.Good info, Ganderite. FYI, the single base ball powders are all of fairly recent manufacture, so to not know about them is no shame! I believe most of them originate out of Belgium, but are marketed in N.A. by Ramshot. I have burned out a few barrels over the years as well, but because I never was too worried about screwing a new one on when the old one showed it's erosion by opening groups, I never really kept tabs on any difference between those I fed D.B./T.B ball powders and those I fed S.B. extruded. I washed up 3 - 220 Swift barrels, 3 - 22-250's, 8 or 9 - 6mm Remington, 2 each - 7mm STW, 7mm Rem Mag, 300 Win Mag. In the 22-250s & Swifts, I shot mostly IMR4064 and H380, the 6mms IMR 4350, W760 & Norma MRP. But as you already know, it takes a fair bit of shooting to destroy a good barrel if it is properly cared for. Regards, Eagleye.
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