Page 1 of 2 12 LastLast
Results 1 to 10 of 12

Thread: Bullet diameter

  1. #1

    Thumbs up Bullet diameter

    There is always such discussion here concerning which calibre is best etc, what I don't hear is a debate on bullet diameter. I'm an advocate of the .30 cal and believe the larger diameter to bullets such as the 6-7mm range aids in gaining increased wound channel. We use expanding projectiles which can be variable, so why not start with a increased diameter to start with?

  2. #2
    Quote Originally Posted by mattmck View Post
    There is always such discussion here concerning which calibre is best etc, what I don't hear is a debate on bullet diameter. I'm an advocate of the .30 cal and believe the larger diameter to bullets such as the 6-7mm range aids in gaining increased wound channel. We use expanding projectiles which can be variable, so why not start with a increased diameter to start with?
    You're right about the wound. I hear people worrying about .458" bullets expanding on deer but if their 6mm expanded to .458 they would say it was a sterling performer. But that said...

    It's a simply a matter of ballistics. A smaller diameter bullet of similar weight has a better ballistic coefficient and greater sectional density. My favorite and oft-used example is that of my brother-in-law who was a professional elk guide in northern New Mexico. He used a 6.5x55 carbine loaded with 160 grain RN bullets to put down wounded elk. They would travel length-wise through a fleeing bull and pile him up at 2300 fps. The 160 grn RN had about the same sectional density as the 30 cal .220 grain.~Muir

  3. #3
    Hi Muir, I agree with the SD and BC argument, however the .30's such as 308 and 30-06 have more than adequate penetration and range in usual hunting ranges.

  4. #4
    SD Regular
    Join Date
    Dec 2008
    Location
    East Midlands M1/M69 Junction 21
    Posts
    5,404
    Between 270 (.277), 7mm (.284) and 30-06 (.308) the difference in bullet diamter in terms of wound channel means nothing. Even an 8mm bullet at .323" is what forty-six thousandths of an inch larger. It makes no difference in like for like bullet construction.

    The real issue is twofold:

    1) About how increased base area enables a bullet to be driven faster for equal pressure as a bullet of smaller base area. Thus a 150 grain 8mm bullet will achieve better velocity than a .308" diameter bullet than will a .277" diameter bullet if limited to the same pressure. Which is why the German 8mm was able in 19o8 to launch at 154 grain spitzer bullet at just over 3,000fps and unheard of velocity for those days and that the USA didn't match until the 250-3000 Savage and the 270 Winchester (both of course with lighter bullets).

    2) Ballistic performance. Small diameter in like for like materiels and construction means a flatter trajectory. Thus a 150 grain 270 Winchester will have a flatter trajectory than a 150 grain 8mm given equal starting velocity. And supposedly that also gives better terminal ballistics as regards penetration.

    As Muir has said regarding the 6.5 Swede.

  5. #5
    Quote Originally Posted by enfieldspares View Post
    Between 270 (.277), 7mm (.284) and 30-06 (.308) the difference in bullet diamter in terms of wound channel means nothing. Even an 8mm bullet at .323" is what forty-six thousandths of an inch larger. It makes no difference in like for like bullet construction.

    The real issue is twofold:

    1) About how increased base area enables a bullet to be driven faster for equal pressure as a bullet of smaller base area. Thus a 150 grain 8mm bullet will achieve better velocity than a .308" diameter bullet than will a .277" diameter bullet if limited to the same pressure. Which is why the German 8mm was able in 19o8 to launch at 154 grain spitzer bullet at just over 3,000fps and unheard of velocity for those days and that the USA didn't match until the 250-3000 Savage and the 270 Winchester (both of course with lighter bullets).

    2) Ballistic performance. Small diameter in like for like materiels and construction means a flatter trajectory. Thus a 150 grain 270 Winchester will have a flatter trajectory than a 150 grain 8mm given equal starting velocity. And supposedly that also gives better terminal ballistics as regards penetration.

    As Muir has said regarding the 6.5 Swede.
    I disagree, it's not the bullet diameter that's important per say, but rather the area of impact that determines the amount of damage produced, hence we use expanding bullets. Increased velocity and flatter trajectory is fine if long range is required 300m + but hi velocity at hunting ranges often reduces penetration.

  6. #6
    Now it's getting convoluted and a little arbitrary. Higher velocity must be matched to bullet construction. When the a fore mentioned bro-in-law was up at this elk reserve, the Remington 7mm Mag was banned as original factory loadings used bullet from their 7x57 loading which caused many elk to be wounded. Likewise, I'm guessing that a Barnes TSX 200 grain 30 cal out of my Remington 788 30-30 would not be much better than a FMJ at 100 yards.~Muir

  7. #7
    Well I think we should set some standards to avoid confusion. If a bullet of sound construction of .30 compared to 6-7mm, at usually accepted ethical MPBR hunting distances of under 300M, hitting at 2,300-3000fps the .30 will be a better killer.

  8. #8
    SD Regular Greener Jim's Avatar
    Join Date
    Jul 2014
    Location
    Yorkshireman in Darkest Cornwall
    Posts
    2,572
    Quote Originally Posted by Muir View Post
    You're right about the wound. I hear people worrying about .458" bullets expanding on deer but if their 6mm expanded to .458 they would say it was a sterling performer. But that said...
    That's me then personally I think bigger is better. Slow bullets cause less meat damage in general and the trajectory is fine for normal deer hunting ranges.
    As Muir, said 6mm to .458 is great expansion. But obviously .458 expanding the same amount (0.889") is a bigger hole and all that with less meat damage.
    I'm surprised we don't have more 30-30's, 45-70's, 303's etc and spend our time knocking stuff over with heavy for calibre bullets

    Realistically though, I think one of the .358's are perfect for game in the uk or one of the lower powered 338's. Both allow just a little more weight.

  9. #9
    Quote Originally Posted by mattmck View Post
    Well I think we should set some standards to avoid confusion. If a bullet of sound construction of .30 compared to 6-7mm, at usually accepted ethical MPBR hunting distances of under 300M, hitting at 2,300-3000fps the .30 will be a better killer.
    Ah. Well, it's hard to say. I'm not being a wise-a$$ but there is still a lot of arbitrary stuff going on here.
    By saying "sound construction" can we agree to identical construction and appropriate for the speeds mentioned? And those speeds are terminal speeds? Because that seems awful fast to me. It would mean that each bullet compared would need to have at least 3000 fps at the muzzle and at least 2300 fps at 300M. And lastly, shall we decide on a game and shot placement? I know for a fact that a 150 grain 7mm bullet at 2700 fps will penetrate farther than a 308 cal bullet fired at the same speed -and perhaps faster. We need to make the amount of vitals the bullet needs to penetrate equal, I'm thinking. For the purposes of this discussion I'll let you decide on the parameters.

    Interesting topic, BTW.~Muir

  10. #10
    Quote Originally Posted by Muir View Post
    You're right about the wound. I hear people worrying about .458" bullets expanding on deer but if their 6mm expanded to .458 they would say it was a sterling performer. But that said...

    It's a simply a matter of ballistics. A smaller diameter bullet of similar weight has a better ballistic coefficient and greater sectional density. My favorite and oft-used example is that of my brother-in-law who was a professional elk guide in northern New Mexico. He used a 6.5x55 carbine loaded with 160 grain RN bullets to put down wounded elk. They would travel length-wise through a fleeing bull and pile him up at 2300 fps. The 160 grn RN had about the same sectional density as the 30 cal .220 grain.~Muir
    This!

    And with the new(isn) monometal expanding bullets, the smaller calibers performance is damn near perfect in consistency.

    You say that the .30s penetration is perfectly fine at normal hunting ranges and you are for the most part correct, but so are the .243s, .257s and .264s, and they do it with less recoil, better external ballistics (for the same weight) and less cost.

    The fact is is that today terminal performance is actually less of an issue in caliber selection. More important IMO are matters of external ballistics, cost, availability and emotion. Don't underestimate emotion as one of the major guiding principles in caliber selection. EDIT*** AND SHOT PLACEMENT OF COURSE.

    My favourite caliber is .264 followed by .284. I never understood the fascination with the .277 caliber. External ballistics of the 6.5mm bullet, weight and velocity being equal, are better and there are no factory loading in heavier projectiles.

    I also love my .30-30. With a 150grain Barnes TSX bullet it can take every game animal here in Canada. There is nothing special about the ballistics of a 150gr .308 caliber bullet, but as you say it's sufficient and I use it as a bush cartridge.

    Where the .308 caliber shines is in the 200-220 grain class. The problem is that at these weights you get more recoil, more powder burn to maintain velocities, and no difference in killing power.

    I really do respect the .308 caliber class, particularly the .30-30, .30-06 and .308. They will get the job done and the latter two do not recoil that bad.
    Last edited by Canadian1; 29-09-2014 at 01:53.

Similar Threads

  1. Wanted RCBS Bullet Puller Collet 27 (270 Diameter)
    By crouch valley in forum Reloading
    Replies: 0
    Last Post: 24-05-2013, 19:25
  2. For Sale Forster: Bullet Puller Collet 31 Caliber (311 Diameter)
    By maffs in forum Reloading
    Replies: 0
    Last Post: 23-10-2011, 16:36
  3. variation in bullet diameter for same calibre
    By bewsher500 in forum Ammunition, Reloading & Ballistics
    Replies: 8
    Last Post: 17-02-2011, 13:16
  4. One for Muir ..... cast bullets and diameter required?
    By Brithunter in forum Ammunition, Reloading & Ballistics
    Replies: 12
    Last Post: 01-06-2010, 23:48
  5. TUBE DIAMETER
    By W16OEN in forum Equipment & Accessories
    Replies: 2
    Last Post: 20-07-2009, 08:14

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •