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Dale Clifford
Optics Jedi Knight Joined: July/04/2004 Location: United States Status: Offline Points: 5087 |
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Posted: February/01/2007 at 11:38 |
Bullet nose deformation can occur frequently when exposed lead or plastic tipped bullets are used. In bolt action rifles it usually isn't the problem as in gas guns. What is your experience? An eagle variant of Armalites AR10 series with chrome lined barrel, 20 rd mags, and Hornady's 155 A-Max bullets are being tested because of their high BC and low wt. allows velocity retention at extended ranges. |
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Dale Clifford
Optics Jedi Knight Joined: July/04/2004 Location: United States Status: Offline Points: 5087 |
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The trigger is stock, with the usual hope, skip and jump.
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rootmanslim
Optics Professional Joined: June/04/2006 Location: Pinedale, WY Status: Offline Points: 557 |
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At practical hunting ranges the trajectory difference between a round nose and spitzer is of no consequence.
My favorite bullet, Barnes TSX, has no nose deformation issues. The only way noses get deformed in the gun is sliding fwd in the magazine which isn't much of an issue in most calibers. If they do slide it is east to silver solder in a 1/2 round guide rib on each side of the magazine to touch the case shoulder and prevent the cartridge from moving fwd.Or you can shoot a Mannilicher or a Savage 99 with the rotary magazines. |
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Bender
Optics Apprentice Joined: December/30/2005 Location: Croatia Status: Offline Points: 80 |
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[QUOTE=rootmanslim] The only way noses get deformed in the gun is sliding fwd in the magazine which isn't much of an issue in most calibers.[QUOTE]
Noses could get deformed while chambering also. |
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rootmanslim
Optics Professional Joined: June/04/2006 Location: Pinedale, WY Status: Offline Points: 557 |
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If they get hit chambering I think that's a real problem as it means the bullet is hitting the bbl face.
(Why I like 03s and M70s with their "unsafe" coned breech). If the feed ramp and bbl alignment is correct the cartridge should enter the chamber and touch nothing until the shoulder enters. That is much easier to do in a push feed gun with a round like the 300 H&H than a 25 WSSM. |
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Bender
Optics Apprentice Joined: December/30/2005 Location: Croatia Status: Offline Points: 80 |
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You are right-that is what I mean. I get these problems with some ammo,and some feed just fine.
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pyro6999
Optics Retard OT TITAN Joined: December/22/2006 Location: North Dakota Status: Offline Points: 22034 |
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my model 70 25 wssm chambers up just as well as my model 70 30-06 so no complaints from me on that.
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They call me "Boots"
375H&H Mag: Yeah, it kills stuff "extra dead" 343 we will never forget God Bless Chris Ledoux "good ride cowboy" |
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rootmanslim
Optics Professional Joined: June/04/2006 Location: Pinedale, WY Status: Offline Points: 557 |
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Well if it's a concern to you, I'd take it to a gunsmith who knows about feeding and chambering.
It might just involve a bit of polishing or magazine tension adjustment to cure. |
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Dale Clifford
Optics Jedi Knight Joined: July/04/2004 Location: United States Status: Offline Points: 5087 |
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OK, probably no big problems with bolts, however in gas guns, 308 20 rd mags, the noses get progressively "hammered" with each cycle of the gun. How is this going to affect practical accuracy, given the tolerances of an AR10. |
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Mike McDonald
Optics Journeyman Joined: September/01/2004 Status: Offline Points: 739 |
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Dale,
You can do alot, I mean ALOT of damage to the front of a bullet with little ill effect. Your gas gun won't do that kind af damage.
Just for fun once upon a time I took my uniformer to the range and shot at steel from 1000 yards. Had to cut 0.040" off the front of the bullet to see any detrimental effect. |
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Dale Clifford
Optics Jedi Knight Joined: July/04/2004 Location: United States Status: Offline Points: 5087 |
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Thanks for the replys- Speer and other sources state small changes front small effect- small changes back large effect. Was wondering what actual expierences were encountered. 2nd part of question, did you notice lower points of impact than anticipated, do to change in ballistic coefficient?
Edited by Dale Clifford |
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rootmanslim
Optics Professional Joined: June/04/2006 Location: Pinedale, WY Status: Offline Points: 557 |
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Dale, I would infer from a recent G&A test where they shot
30-30s with spire points against flat noses and found no real world difference (out to 200) in accuracy or trajectory, that bullet deformation is another urban legend IN THE WORLD OF HUNTING. I'm sure for 1000 yard shooters, it's another undesirable variable to be eliminated and could cause flyers. easy enough to do a test by smashing up some lead spire points or plastice tipped bullets and shooting them against pristeen ones. Dare I say yet another reason to use TSXs? |
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Tip69
Optics Master Extraordinaire Tip Stick Joined: September/27/2005 Location: Nebraska Status: Offline Points: 4155 |
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carefull there Root.......... don't want to get "flamed" again |
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take em!
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Dale Clifford
Optics Jedi Knight Joined: July/04/2004 Location: United States Status: Offline Points: 5087 |
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My concern was A-max 155 gr in 20 rd. AR mags to 600 yds on 8 steel targets under time pressure. With the 3 to 15 X NF and NP1 reticle, it is possible to center at 400 use the top part for 100 yd shots and then correct prob. drop at ticks out to 600 without going to dial in. It doesn't matter if the deformation causes changes only that it is consistent.
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rootmanslim
Optics Professional Joined: June/04/2006 Location: Pinedale, WY Status: Offline Points: 557 |
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Dale, you are right. That's why I started a TSX thread
in the reloading section.A Maxs are great. Whenver I get a new 30 cal, they are my test bullet to see what the rifle is capable of before proceeding to hunting loads. |
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Dale Clifford
Optics Jedi Knight Joined: July/04/2004 Location: United States Status: Offline Points: 5087 |
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No question on the TSX's ---- I just need a good deal on 3000.
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rootmanslim
Optics Professional Joined: June/04/2006 Location: Pinedale, WY Status: Offline Points: 557 |
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That quantity might be worth a call to Ty @ Barnes.
Gotta believe there is room in them at that level. |
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Mike McDonald
Optics Journeyman Joined: September/01/2004 Status: Offline Points: 739 |
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Dale,
I use Tubbs uniformer on my NRA F class stuff. For a 0.005" cut I see less additional drop than I can hold at 600 through 1000 yards for 20 shot groups. At 0.015" I see about 1/8th moa at 600 and 800, 1/4 moa at 1000. At 0.030" it seems to be at the extreme end of stability and groups open up alittle. Additional drop is aver 1/2 moa at 1000, telling me that this is too much trimming. At 0.040", just to see what happened, at 1000 yards I could keep the bullets inside the target frame but that's about it.
I've run alot of 168 amax through the AR10 with no ill effect.
Speer is correct, the front of the bullet is almost flying in a vaccuum. The rear has to uniformly deflect about 4000 psi gas pressure at the muzzle. Ding up the back of the bullet and you're all done. |
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Dale Clifford
Optics Jedi Knight Joined: July/04/2004 Location: United States Status: Offline Points: 5087 |
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Thanks mike --the specifics I was looking for. F class stuff is tighter spec than I need --which means it should work great for this project.
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