Flat Based bullets vs Boat tails

[BoydAllen]

finnnaddict,

It may be a barrel twist thing. I had a .308 that did not like light bullets. It had a 10" twist. The longer BTs did much better. On the other hand, with a suitable throat and a twist rate that was tailored to short range benchrest, the longer BTs would never stabilize. Specialized rifles have the edge when used in the event that they were designed for. A friend has shot some amazing groups with his 6BR using factory Lapua ammo. What size are your AVERAGE five shot groups?

 

[spclark]

It may be a barrel twist thing. I had a .308 that did not like light bullets. It had a 10" twist. The longer BTs did much better. On the other hand, with a suitable throat and a twist rate that was tailored to short range benchrest, the longer BTs would never stabilize.

Very much so! Longer bullets need faster twists to stabilize, that's a fact. Where a light weight (relatively shorter) might work in a fast twist (within reason; over-stabilization can happen!) a heavy weight (longer) won't work with a slow twist.

What are typical long range BR twist rates? For score shooting they run from 1:7.5 or 1:8 in 6mm to maybe 1:14 in 308 though current trends see 1:10 - 1:12.

 

[Eddie Harren]

Butch, you're wasting your time. Most of these people don't even know who you are referring to.

 

[lpreddick]

short range fb vs bt bullets: one significant difference between these bullets is that the fbs have a "pressure ring". you can see the buldge of this ring in the neck. this suggest the bearing surface of the bullet in front of this buldge is ever so slightly "loose" in the neck and when seated .020+ into the lands, a slight runout might be corrected....001-.002. this ring acting as a pivot point to more precisely align the bullet....just hypothesising. i suspect light weights with a bt behave pretty much as fb. the long bts on a vld is a different thing and does seem to improve trajectory by reduced drag, etc.

 

[finnaddict]

finnnaddict,

It may be a barrel twist thing. I had a .308 that did not like light bullets. It had a 10" twist. The longer BTs did much better. On the other hand, with a suitable throat and a twist rate that was tailored to short range benchrest, the longer BTs would never stabilize. Specialized rifles have the edge when used in the event that they were designed for. A friend has shot some amazing groups with his 6BR using factory Lapua ammo. What size are your AVERAGE five shot groups?

BoydAllen,

Same here with light bullets. Bullets weighing in at 185 and up to 200 grs perform best for me using HPBT Match and FMJBT Match. I have a 1-10 twist also. The rifle was designed for specific bullets, the Lapua D46 to be exact. My average 5 shot groups at 100yds off the bench are 1" +/- 0.100". The rifle has done less than that in the past. At 200 yds, 10 shot groups are still MOA. I am looking at trying out some 220 HPBT Match bullets in the near future. Maybe I can tighten those groups up some more. This particular rifle is 81 years old.

 

[broncman]

The best five shot groups I personally have ever shot are from a 20" 1in 10 twist 308 with a long throat...... Using flat based 125 grain bullets.... Jumping a long ways!

Cant explain it...

 

[Beau]

Same here with light bullets. Bullets weighing in at 185 and up to 200 grs perform best for me using HPBT Match and FMJBT Match. I have a 1-10 twist also. The rifle was designed for specific bullets, the Lapua D46 to be exact. My average 5 shot groups at 100yds off the bench are 1" +/- 0.100". The rifle has done less than that in the past. At 200 yds, 10 shot groups are still MOA. I am looking at trying out some 220 HPBT Match bullets in the near future. Maybe I can tighten those groups up some more. This particular rifle is 81 years old.

What does this have to do with short range benchrest/the ultimate in short range accuracy? This is comparing apples to trucks.

 

[22BRGUY]

Butch, you're wasting your time. Most of these people don't even know who you are referring to.

You're right on this Doc...but we can always learn if we want to.

 

[finnaddict]

Same here with light bullets. Bullets weighing in at 185 and up to 200 grs perform best for me using HPBT Match and FMJBT Match. I have a 1-10 twist also. The rifle was designed for specific bullets, the Lapua D46 to be exact. My average 5 shot groups at 100yds off the bench are 1" +/- 0.100". The rifle has done less than that in the past. At 200 yds, 10 shot groups are still MOA. I am looking at trying out some 220 HPBT Match bullets in the near future. Maybe I can tighten those groups up some more. This particular rifle is 81 years old.

What does this have to do with short range benchrest/the ultimate in short range accuracy? This is comparing apples to trucks.

Pardon me. Thought the topic was Flat based bullets vs Boat tails.

 

[stinnett1981]

My experience with flat base bullets (53 grain Sierra Matchkings) is great. Thats all I shoot now at 100 yard matches. Im shooting a factory Rem 700 .223 9 twist. I started out shooting boat tail 69 grain Sierra Matchkings and they shot .7 moa at 100 yards on average. All the other boat tails shot around .9 moa at 100 yards which is decent for a factory rifle IMO. Then I bought some 53 grain flat base Sierra Matchkings and they shoot .4 - .5 moa at 100 yards. They shoot hands down the best at short distances for me. The 60 grain flat base Hornady V-Maxs shoot better than any boat tail at 100 yards too. Past 100 yards I shoot the boat tails.

 

[M14AMU]

I'm kinda partial to FB bullets!


Untitled by Sharps45 2 7/8, on Flickr

 

[JDMock]

Rick, those bullets look awfully corroded! ;D James

 

[M14AMU]

Rick, those bullets look awfully corroded! ;D James

But...but...they shoot like this using aperture rear sight with post front!


540 yard AR400 Clanger by Sharps45 2 7/8, on Flickr