Lead Free Bullets & Increased Pressure

[Gobble Gobble]

I recently purchased my wife a 30-06 for Mule deer and Bear, I had planned to reload some Barnes TTSX in 168 gr. but have yet to decide on a powder as I have more ballistic tests to read up on. My wife was talking reloading with her brother tonight and they got onto the topic of lead free bullets from Barnes and Hornady and he went on to tell her about an article he had read that said because copper is lighter than lead the bullets are made longer thus, they have to be seated deeper (already knew this). He said because of the bullet being seated deeper it will create added pressure due to less air space for the gasses to expand (knew this as well). Due to the increased gas pressure more barrel heat will be created, she is now worried the barrel will get to hot and possibly bulge or split under the increased pressure as well as premature barrel wear. Her brother stated that she should not load to max grains but rather subtract 10% from max grain and use that number for her new max charge. I have not read any information on this.

So, my question for all you is… Just how much is the pressure increased (I’m sure it depends on the powder used) having to seat a lead free bullet deeper verses a lead core bullet? Is there any real increase in barrel heat, wear and the possibility of barrel damage due to the increased pressure? How about loading to 10% less max charge? My wife prefers to load to max charge I like to go a grain or two less depending on what I’m loading for. Any info would be appreciated.

[bobcat]

I'm no expert but I don't think there's much of an increase in pressure from seating a bullet deeper in the case. Sure, maybe a little, but not significant. The extra pressure you're going to see from copper bullets versus lead bullets IS due to them being longer though. The longer bullet naturally will have more bearing surface (the amount of the bullet that is in contact with the bore) and that is what will give you the increased pressure. This is why Barnes bullets have the grooves- it gives the copper material somewhere to go as the bullet is forced down the barrel, and helps to keep pressure down.

Also, you won't necessarily need to seat the bullet deeper in the case. If you're not limited by the length of the magazine in the rifle, then you can just load them to the same depth as before, the overall length will just be slightly longer.

Another thing, with the pure copper bullets you can afford to go lighter than you would with a standard jacketed lead bullet and still get the same, or better, performance. With the 30-06, I think a 150 grain Barnes would be great for anything. The extra velocity will help in expanasion, especially at longer ranges when it will have slowed down some.

You should still start your load development well below the max charge listed in your book and work your way up. But your pressure with the max load you end up with shouldn't be any higher than what you would have with a lead bullet.

[bobcat]

I found some interesting information on the Barnes website that is relevant to this topic:

Comparing Bullet Length

How important is bullet length? Longer bullets have a higher ballistic coefficient (BC), which means more retained energy and flatter trajectories for long-range shooting. They also align better within the bore, promoting greater accuracy. These are some advantages long bullets offer.

On the other hand, long bullets project farther into the cartridge case, limiting powder capacity. Extremely long bullets may compress powder charges, particularly in short-action cartridges loaded to standard overall length. Long bullets are more likely to promote fouling, and require a relatively fast rifling twist to properly stabilize en route to the target.

Some have mistakenly thought Barnes’ all-copper Triple-Shock X Bullets were (a) longer than competing premium bullets, and (b) caused pressure and fouling problems because of the perceived greater surface area contacting the bore.

Here are the facts:

When a 160-grain 7mm Barnes Triple-Shock X Bullet was measured against Speer Spitzer SP, Nosler Partition, Hornady SST and Nosler AccuBond bullets of the same weight and caliber*, the Triple-Shock was longer than the Speer Spitzer and Nosler Partition, but shorter than both the Hornady SST and Nosler AccuBond bullets.

(* The Hornady SST weighed 162 grains.)

When 180-grain .30-caliber projectiles were compared to a Barnes Triple-Shock X Bullet of the same weight and diameter, the Triple-Shock bullet was longer than Sierra Pro-Hunter, Combined Technologies CT Fail Safe and Nosler Ballistic Tip bullets, but shorter than the AccuBond and considerably shorter than the Swift Scirocco.



Longer than some, shorter than others, Triple-Shock bullets are of approximately average overall length.

There’s more! “Bourrelet” describes the length of the bullet that actually comes in contact with the rifling. Multiplied by bullet circumference, it determines the surface area engraved by the lands and grooves as the bullet passes through the bore.

Barnes Triple-Shock X Bullets have an average overall length, but less surface area contacting the bore. How is this possible?

Multiple grooves machined into the shank of each Triple-Shock X Bullet reduce the bullet’s surface area that contacts the bore, while bourrelet length remains unchanged. The result? Triple-Shock X Bullets create less fouling and pressure buildup than almost all competing bullets. Their unique, one-piece design and generous bourrelet produce unsurpassed stability and exceptional accuracy. With no lead core to fragment or shear away, Triple-Shock X-Bullets retain virtually 100 percent of their original weight for deep, sure penetration.

[bobcat]

There's a thread on 24 Hour Campfire I refer to once in a while to get ideas for my 30-06. It's rather long as it's been up for quite some time but there's some good info in there if you have time to look.


http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/3216390/Good_30_06_Loads#Post3216390

[Bob33]

Here is a real good reference: http://www.hornady.com/ballistics-resource/internal

(I don't know how much of a pressure difference there is due to seating the bullet deeper per se, but there is definitely a difference in pressure depending on how far the bullet has to jump to engage the rifling):

To illustrate the effects of variations in bullet travel before the bullet enters the rifling, we'll compare a standard load with adjustments made only in the bullet's seating depth.

In a "normal" load with the bullet seated to allow about one 32nd of an inch gap (A) between the bullet and the initial contact with the rifling, pressure builds very smoothly and steadily even as the bullet takes the rifling. Pressure remains safe throughout the powder burning period (B), and the velocity obtained - 3500 fps - is "normal" for this load in this rifle.

Seating the bullet deeper to allow more travel before it takes the rifling, as in these next two illustrations, permits the bullet to get a good running start (C). Powder gases quickly have more room in which to expand without resistance, and their pressure thus never reaches the "normal" level. Nor does the velocity; with the same powder charge it only comes to 3400 fps (D).

When the bullet is seated to touch the rifling, as in the accompanying illustrations, it does not move when the pressure is low (E); and not having a good run at the rifling as did the other bullets, it takes greatly increased pressure to force it into the rifling. As the rapidly expanding gases now find less room than they should have at this time in their burning, the pressure rise under these conditions is both rapid and excessive (F). Velocity is high at 3650 fps - but at the expense of rather dangerous pressure. Many rifles deliver their best groups when bullets are seated just touching the rifling. Seating bullets thus can be done quite safely if the reloader will reduce his charge by a few grains. The lighter load will still produce the "normal" velocity without excessive pressure.

[high country]

the only way yo will blow a barrel on a 30-06 with a 168 tsx is by using LOTS of powder that is WAY too fast. the grooves are to help the bullet slug up like a traditional bullet, if you ever fired xbt's or xlc's you know how much they help. the best thing to do is find a accurate load, and there are lots of good combos for that case/bullet, and go shoot it. there are many tsx's been launched with way more pressure then you are gonna push and we are all still alive.

[Gobble Gobble]

Thanks for the great info and links. I was never really worried but the misses can be a bit of a worry wart when it comes to re loading and possible damage to HER guns.

[mazama]

Barnes recomends using more powder,because of less surface area.

[C-Money]

Powder wise, look at IMR 4350.

[Gobble Gobble]

I cant find my notes but IMR 4350 was one and IMR 4064 was another powder I have thinking of using.

[bobcat]

I like H4350 but IMR 4350 is good too.

[bobcat]

Here's some more good reading for loading the 30-06:

http://www.24hourcampfire.com/newsletters/May_2009.html

[Crisptrigr]

GG,
Much of the information you shared with us in your original post regarding what your wife's brother told your wife is incorrect.
Perhaps he mis-understood the article or the info. in the article was inaccurate.

[timberghost72]

Powder wise, look at IMR 4350.

I used this powder at 54 grains with 165 gr Barnes TSX and had excellent groupings.

[MDGrand]

Just started reloading myself and had a question about where on the internet I can find the best Barnes recipe for 300 RUM, including max COAL specs, min/max grains, etc?

Anybody here that can reply with a few links before I start a search over the internet?

[whacker1]

Added thought for the conversation .  The Nosler E-tip is smooth and longer than the accubond - and thus longer than the Barnes mentioned.  The E-tip  being longer makes it one of the longer bullets available.  This bullet does have a great deal of surface area contacting the riflings vs. the Barnes.  I did not have any pressure signs in my 300 RUM, but two observations.  It kicks like a mule shooting the E -tips and I could not get it to punch paper very well.  Anyone else have any luck with the E-tip? 

Currently my best is the 168 Berger VLD, which is going the opposite direction for retention of mass.  But it flys good.  and was plenty fatal at 40 yards this year.

[timberghost72]

Just started reloading myself and had a question about where on the internet I can find the best Barnes recipe for 300 RUM, including max COAL specs, min/max grains, etc?

Anybody here that can reply with a few links before I start a search over the internet?

The Barnes website has load data for their bullets

http://www.barnesbullets.com/

[Curly]

Just started reloading myself and had a question about where on the internet I can find the best Barnes recipe for 300 RUM, including max COAL specs, min/max grains, etc?

Anybody here that can reply with a few links before I start a search over the internet?

As far as COAL goes, just determine what length puts your bullet at 0.050" from the lands and start there.