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Ballistic tip problem |
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trigger29
Optics Master Extraordinaire X = 180 Y = 90 (X+Pyro)+(Y-Pyro) = ? Joined: September/29/2007 Location: South Dakota Status: Offline Points: 4353 |
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Posted: January/03/2008 at 08:44 |
I have been shooting a Weatherby Vanguard in .270 WSM (sorry pyro) for the last couple months. With 150gr. Winchester powerpoints it groups about 1/2" @ 100. I planned to try some Winchester ballistic silvertips for deer this year for the higher ballistic coeffiecient, but groups went to about 4-5" with 130gr. I tried a box of them in 150gr. with the same results. Could this be the black oxide coating that Winchester uses on the bullet, or more the gun just not liking the ballistic tips? I also noticed a couple of these rounds wouldn't chamber in my gun. Iwould push them up into the chamber and couldn't close the bolt completely. I took the gun home and cleaned it completly spotless and tried again with the same results. The rounds not chambering really bothers me, but I don't know why it would happen. What steps would you guys take to find this problem and correct it. Thank you.
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"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed." |
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8shots
Optics Jedi Knight Lord Of The Flies Joined: March/14/2007 Location: South Africa Status: Offline Points: 6253 |
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Just a guess, but maybe the OCL (overall cartridge length) is too long on the Silvertips. It maybe that due to a different ogive (fat part of bullet) the bullet cannot go forward enough when chambering the round. It is therefore tight against the lands, which is not good for most rifles, as a slight jump is required. Hand loaders can adjust the OCL themselves to suit their own rifle's particular likes and dislikes, thereby improving accuracy.
By asking a handloader to move the bullet in a fraction and testing it for the bolt closing you may find this is the problem if the bolt closes easily on a shorter bullet.. DO NOT FIRE THIS ROUND AS UNKNOWN PRESSURE CAN CAUSE DAMAGE OR INJURY. A safer way may be to blacken the bullet with a koki pen or soot and chamber it. The area where the bullet jams onto the lands may show up.
If this is the problem with these bullets it will also explain your loss in accuracy. Edited by 8shots - January/03/2008 at 09:04 |
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pyro6999
Optics Retard OT TITAN Joined: December/22/2006 Location: North Dakota Status: Offline Points: 22034 |
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i will tell you i had similar results with both my 300wsm and my 25wssm that the plain jane super x power points would out shoot the ballistic tips all day long and i wondered why, and was some what pissed because the bts cost a lot more than the super x's did. now about your rifle sounds to me like you may have a short throat, not a real big deal, you can send it to wby and they will fix it, or you can start handloading and fix the problem with shorter case and deeper bullet seating and save a lot of money. higher b.c doesnt always mean better groups it does mean flatter shooting especially at longer distnaces, but with the 270wsm, you are already shooting a very flat line as it is. i would try some different bullets other than the bt's the accubond is very similar but the bullet of course is a little bit better built but the bc and sd are very close. keep trying different makers bullets, i would try some federals if they make them for the 270wsm.
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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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trigger29
Optics Master Extraordinaire X = 180 Y = 90 (X+Pyro)+(Y-Pyro) = ? Joined: September/29/2007 Location: South Dakota Status: Offline Points: 4353 |
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Correct me if I'm wrong, but a short throat could be a good thing. With throat erosion happening all the time, I just got more meat there to erode. I understand what pyro was saying about ballistic coefficient. I was going to shoot them because the shots out here in the west can be long, and in South Dakota the wind just never quits. Maybe I will sucker someone into hand loading me some Nosler ballistic tips or accubonds for me. Would help if I knew how to measure how far it is to the lands in my gun. And where should I start for spacing the bullet off the lands?
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"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed." |
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pyro6999
Optics Retard OT TITAN Joined: December/22/2006 Location: North Dakota Status: Offline Points: 22034 |
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that will do what you need just gotta buy the .270wsm shell for it Edited by pyro6999 - January/03/2008 at 15:22 |
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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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Focus
Optics Master Conquistador!! Joined: June/05/2007 Location: Maine Status: Offline Points: 1006 |
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If you have a dial caliper measure one that will chamber vs one that won't see if they measure a different length. Factory ammo is usually pretty short so it would take a pretty short throat to effect most factory ammo within saami specs. Spec's are 2.860 for that round, see if they measure longer than that. See if one that don't want to chamber will have any marks on the bullet about 1/3 way down from the rifling. Other than that it could be brass not the right size.
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pyro6999
Optics Retard OT TITAN Joined: December/22/2006 Location: North Dakota Status: Offline Points: 22034 |
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the brass should fit its factory ammo
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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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Focus
Optics Master Conquistador!! Joined: June/05/2007 Location: Maine Status: Offline Points: 1006 |
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Yeah agreed but its always a possibility that it was produced off size or that something went amiss in the loading process. Winchester has farmed out a good bit if not all their ammo production to other companies. I bought a couple of the white box ammo for my 22-250 a couple years ago, first box shot fine and was shooting 1/2" groups (great for any factory ammo!) next box had two in a row lock the bolt up from pressure and the primers were bleeding and the third blew the primer and shot out the vent port on my action. Called winchester and they referred me to some other company that had actually loaded it for them. They offered me another box....... Focus |
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pyro6999
Optics Retard OT TITAN Joined: December/22/2006 Location: North Dakota Status: Offline Points: 22034 |
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usually if the ammo doesnt fit its the gun factory ammo has specs they must meet for oal, not to say you are wrong anything is possible, but i think he has a short throat
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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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Focus
Optics Master Conquistador!! Joined: June/05/2007 Location: Maine Status: Offline Points: 1006 |
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Yeah if its truly saami spec or under......I gave the saami OAL so if he can throw one on a dial caliper he will know if the ammo is within spec. I once saw a situation where the recoil was causing bullets to pull out of the case slightly to the point where they wouldn't chamber. Anything is possible I guess...
If trigger lived close to me it would take about 10 minutes to see how long a throat his chamber has and we could measure his cartridges as well. After doing OAL for reloads and moving bullets in and out so much its all pretty easy to measure and figure out. Focus Edited by Focus - January/03/2008 at 17:12 |
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RONK
Optics Master Extraordinaire Joined: April/05/2007 Location: United States Status: Offline Points: 3199 |
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8 shots' idea of blackening the cartridge with soot will tell you immediatly where to make corrections.
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Focus
Optics Master Conquistador!! Joined: June/05/2007 Location: Maine Status: Offline Points: 1006 |
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Ronk, it will with the case but correct me if I'm wrong but aren't the bullets black?
Focus |
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I Can See Clearly Now......<><
If Accurate rifles Are Interesting.....I've Got Some Savages That Are Getting Mighty Interesting...... |
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RONK
Optics Master Extraordinaire Joined: April/05/2007 Location: United States Status: Offline Points: 3199 |
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LOL! , that didn't occur to me!
I don't know, but if they are black, he might have to look very closely! ( If the bullet is contacting the rifling hard enough to make chambering difficult, the lands will bite the bullet enough to see the marks all the way around the ogive, even without needing to smoke the cartridge.)
Can't hurt to try, and he can do it for free, and right now.
Edited to add: You're right, Focus. They are black oxide(?) according to the O.P. Edited by RONK - January/03/2008 at 20:06 |
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Bigdaddy0381
MODERATOR Georgia peach Joined: February/27/2007 Location: Georgia Status: Offline Points: 13682 |
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Paint a bullet with ( white out) seat it with no powder or primer. slowly close bolt when it stops pull the shel out seat bullet a little deeper and then paint mark.just repeat steps untill the bolt closes easy and see how verything else gose togather and will work from there.
I have a gun the has a ton of jump but one of the best rifles I have ever shot. I also have one thats so close to the AOL the if i'm over.001 with my seating deepth I might be cleaning powder out of the action of the gun from bullet stick.
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8shots
Optics Jedi Knight Lord Of The Flies Joined: March/14/2007 Location: South Africa Status: Offline Points: 6253 |
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Trigger,
You need first to identify if OCL is in fact the problem with the ballistic tip. I hesitate to say this, but take a cartridge with which the bolt closes with difficulty and tap the bullet deeper into the shell by using a suitable odject, like the handle of a hammer. Only move it back very little, about 4thou of an inch. See if the bolt will now close easier. If so, then the OCL of the silvertips are wrong for your rifle.
You should then not use this brand and consider others with the correct OCL, or handload.
Measuring the OCL from tip to primer may not give the correct result. You need to measure from primer to end of bullet ogive, which is difficult without the correct tool. Hence the need to actually chamber the round and see how it fits.
Again, do not fire this round, as a deeper seated bullet has higher pressure curves and can cause damage and or injury.
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mwyates
Optics Master Joined: June/15/2004 Location: Texas Status: Offline Points: 1196 |
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This is the highly technical formula I use for load development: 1. Load 30 cartridges; 6 ea of 5 different powder charges; same bullet. Shoot 2 3 shot groups of each.
Results: No load shoots good - get a differnt bullet and repeat above
Load shoots good - load more and keep shooting
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pyro6999
Optics Retard OT TITAN Joined: December/22/2006 Location: North Dakota Status: Offline Points: 22034 |
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i take it a step further than that, if have 5 powders i load up 75 rounds i do three different weights with each powder and work from there, i shoot three shots out of each five and if the first three dont look promising i dont shoot the last two, if the first three look good then i shoot the last two. then i start looking for a different bullet
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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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Dolphin
Optics Master Joined: October/05/2006 Location: North Carolina Status: Offline Points: 1795 |
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trigger29, did the BTs when chambering require you to put more pressure on the bolt to close it. I have had varying results with BTs on many of my rifles. If your bolt is closing with the same amount of perceived pressure, I am going to make this simple, I doubt the ogive of the bullet is being jammed against your lands. It is not unreasonable to check with some dykem blue or marker of some sort, but with the cartridge passing through the chamber and rubbing against the walls, interruptibility may be difficult. Now, it may be simply the distance from the lands to the ogive and the jump that differs between the two cartridges that is affecting your accuracy and obviously it prefers the power points. General dictum states that excessive free bore decreases accuracy, with all other things being equal. Contrary to popular belief, excessive free bore will decrease the build up pressure and initial velocity while allowing a longer powder burn, while less free bore does the opposite. Some rifles are designed with more free bore and are optimized to shoot more accurately in the caliber that it was designed for. Basically, your rifle prefers the power points. I have many rifles that shoot less than one inch groups with Rem. core lokts and when I switch to a more streamlined bullet like BTs, the groups spread significantly. This is on several rifles of different brands, so all of the chambers cannot be too short. Edited by Dolphin - January/05/2008 at 07:51 |
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pyro6999
Optics Retard OT TITAN Joined: December/22/2006 Location: North Dakota Status: Offline Points: 22034 |
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well guys i talked to trigger and he figured out the problem, a chunk of the black coating came off a bullet and just kinda rest at the edge of the chamber and this is what was causing the trouble, he cleaned it out and no more problem
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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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Focus
Optics Master Conquistador!! Joined: June/05/2007 Location: Maine Status: Offline Points: 1006 |
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Sorry guys......but I hate those bullet coatings. Maybe some like em' but I don't have any use for any kind of bullet coatings that also coat the bore, blue, black, or grey they all turn me off. Glad you found your problem Trigger....
Focus |
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I Can See Clearly Now......<><
If Accurate rifles Are Interesting.....I've Got Some Savages That Are Getting Mighty Interesting...... |
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