Flat base vs boattail bullets

hadjii

So, I have another question about loading for my win 70 in 25-06. Looking over all my load data that I recorded for this rifle, an interesting anomaly popped out at me. On virtually every load I've tried, my most consistent loads have all come from boat tail bullets. Whether 100 grain, 115 or 117 grain, it really didn't seem to matter, boattails were always more consistently accurate than flat base, and for what it's worth, the nosler partitions, whether the 115 or the older 117 grain, were always the least accurate, and the hornady 117 boattails always the most consistent. Just wondering if this is weird or unusual, or if it's just me. Can't quite figure it out.

Butchdog2

On the average a boat tail bullet will be more accurate, longer and better ballistic coefficient.

Hunting bullets are usually less accurate, just the nature of the beast.

Sometimes accuracy is more involved than just bullets. Brass, primer, powder, operator, and firearm all play a big part in the final result.

Okie743

You say you can't quite figure it out.
Speaking from experience working up loads for consistent accuracy for hunting rifles
You have done a good job of figuring it out. You have determined WHAT THE GUN LIKES instead of what you would like for the gun to like. You might test another same type rifle, same caliber and it not like your existing recipe. It's mainly barrel harmonics.
and Yes about Nosler Partition bullets or most any bullet designed as a hunting bullet for large game will usually be little less accurate, because they are not  silhouette  or target bullets. 
Listen to the gun when you are testing. It's trying to tell you something about what it likes for accuracy AND
have fun testing reloads for max accuracy.

nononsense

Looking over all my load data that I recorded for this rifle, an interesting anomaly popped out at me. On virtually every load I've tried, my most consistent loads have all come from boat tail bullets.

I think the word 'anomaly' if a good choice. There are generalities we can observe and record but as a point of fact, every rifle is an individual unto itself. There are no absolutes which apply to every rifle rifle and every load. So it's likes and dislikes are dependent on the testing you run to find the sweet spot and balanced load for your rifle.

I test dozens of rifles and cartridges a year and I have found some generalities to remain true but there are always the variables found in the process of reloading. In your situation, you probably have a 1:10 twist which can affect the type and style of bullets which respond best to your loads.

In general, those flat base bullets respond best to the slowest twist rate which stabilizes the bullet length. Check the benchrest shooters and that's nearly all they shoot is short jacket flat base bullets.

and Yes about Nosler Partition bullets or most any bullet designed as a hunting bullet for large game will usually be little less accurate, because they are not  silhouette  or target bullets.

There are always exceptions and the Berger Hunting bullets will usually outperform most other bullets even though they are labeled as 'hunting' bullets. You have to pay attention to the jump though. Also, I've had exceptional accuracy from Nosler Partitions even though their BCs are lower than the hunting VLDs. I've had them shoot one-hole groups at 100 yards up to a little over 1/2" from other rifles.

These observations are from rifles built with custom barrels, not factory barrels, so your mileage may vary.

Best.

kidthatsirish

It's always good when you find the load your rifle likes! Turns out my hunting rifle prefers flatbase bullets my self.

If you don't mind me ask what kind of powder are you using?

kidthatsirish

Why is it a reject to you for a rifle to shoot better from a fouled bore? I know lots of folks who will check zero one last time prior to start of season, then, at seasons end, clean the rifle.

Is it that you just prefer to start each hint with a clean bore or do you hunt with a rifle that fouls quickly (i.e. muzzleloader or purely cast bullets?)

Or is it just a personal preference?

Canmiss.

I would think that a flat based hunting bullet, like the Nosler Partition bullet could not be as precision formed, cast or lathed as it was meant to drop the game not win a accuracy contest. They have dropped almost everything I have shot with a single shot, 2 on one barren ground caribou. Trophy black bear, caribou, fat Kansas whitetails. The bear was on Vancouver Island and we weren't allowed into the carcass to take anything except its' outsides, the bullet was just under the thick fat on the opposite side. Right rear rib cage entry, almost exiting behind the left foreleg, the bullet was mushroomed out well, but intact. A front leg came up and the critter just rolled over and quit. 19 5/16" on the skull, and about 8'6" on the square. Shokkey was the OF.  

Hawk Carse

I figure game bullets in a hunting rifle are a crapshoot, you have to try enough to see what works.
Benchrest shooters at 100-300 yards use flat base bullets, they are generally more accurate.
Target shooters firing at mid- and long range use boattail bullets because they have a higher ballistic coefficient and will shoot "closer to the wind" and carry supersonic velocity to greater ranges.

bpost

In my 22BR Encore the 52gr Berger FB bullets performs best.  When testing AR type rifles I find that same bullet to be the best bet for accuracy at 100 yards.

mclaiborne

Boat tails are the "fly-better-bullet".....and Partitions have crappy accuracy in every round I have loaded them in, 30-06, 308 243, 22-250 and 223....

Butchdog3

Like me, a slow reader has just joined in.

Okie743

Another thought:

Seen an article few days ago that guy that writes about shooting and reloading said that consistently shooting boat tail bullets vs flat base bullets that the throat area of a rifle would erode faster when using the boat tailed due to the base of the boat tail bullet producing a blow torch funneled gas towards the throat where as with the flat base bullet the majority of the hot gas remained behind the bullets flat base.

HMMMMMMM

yoshmyster

I remember seeing a video between flat and boat. I remember flat "sealed" better. that's about all I remember from that video.

Horse Plains Drifter

Well, once you think about that it is certainly plausible.