Loss in accuracy shooting 55-75g bullets in :8 twist?

[NZVarminter]

It looks like a 1:8 twist is the most popular twist for the 6BR as you need a min 1:8 to shoot the heavier 108 g VLD's and everything i have read says this twist wil also handle the lighter bullets.

..But is there any loss of accuracy shooting the lighter 55-75g bullets with this twist?

Cheers


Grant

 

[CatShooter]

It looks like a 1:8 twist is the most popular twist for the 6BR as you need a min 1:8 to shoot the heavier 108 g VLD's and everything i have read says this twist wil also handle the lighter bullets.

..But is there any loss of accuracy shooting the lighter 55-75g bullets with this twist?

Cheers, Grant

You hear a lot about 8" twists, but there are probably more 14", 12" and 10" twists out there.

If you don't need to shoot bullets over 90 grains, the 8" twist is a handicap.

Fast twists can shoot light bullets well, but it often takes a lot of work to find a load that will shoot - but the slow twists will deliver very good groups on the first day at the range.


.

 

[expiper]

Hi Donovan ...I hear lots-0-folks say that an 8 twist wont shoot the lil bullets....maby that is so from their experience...but..I will never forget the first time I tried "B"enchrest bullets in my first 8 twist bbl...I had aprox 1500 rds of the big un's thru that particular bbl...and was shooting it along with one of my "conventional" 14 twist bbls ...there was the bullets-powder-etc rite there on the loading bench...sooooo ...I thought ....why not....and loaded a culpla of em ...and culdnt believe my eys.....over the yrs I have found that not all bullets under 80 grs can take the rotational speed at the velocity and rpm's from an 8 twist bbl...and think that most people who have had bad results are using a bullet that wasnt up to the task....The very best lil bullet that I have used in my 8 twist guns is the Fowler 66 and other "botuique" bullets with similar ojive/profile...Roger

 

[CatShooter]

Paul -- Are you talking from personal experience with 8-twist barrels?
or is your input based from Sg and/or spin rate and/or mathematical type scenario's?

Personal experence with 9" barrels in 6mm and 7" barrels in 224.

I'm not saying that they WON'T shoot light bullets, just that it might be more difficult to find a light bullet combination that shoots well.


.

 

[Forum Boss]

A good fast twist,1:8") barrel WILL shoot the shorter bullets surprisingly well. And I don't think it takes a lot of work to get them to do so.

In my 8-twist 6BR,Pacnor) the first time I tried the Berger 80s they grouped in the high ones with a "loading book" load of N135, bullets .010" into the lands. The first five shots I tried went in about 0.170".

Just last week Bruce at MT Guns was complaining that the 105s weren't reaching his expectations in his new 8-twist 6BR. I suggested the Berger 80s. He tried them and his groups shrunk in half.

I will agree that if you don't want to shoot the 95-108gr bullets you might as well run a slower twist. But... a good 8-twist isn't going to hurt you that much.

 

[Hammer47]

Happy to read the above posts as I have a recent Savage/ Krieger 8 twist build that is ho hum with the 105 Bergers but a real MACHINE with the Berger 80's. Got no idea why that's just the way it is.

 

[squirrelduster]

I shoot the 75 vmax in an 8 twist Hart. Just a standard book load of 32.5 gr of Varget. Shoots dime groups at 200 yards. Very deadly on squirrels to 400+.
Good luck.

 

[expiper]

hey Hammer...if your 8 twist bbl didnt shoot the 105's ...there is something prolly wrong with the load...that is the long range bullet of the century....go bak and change something ...it will get better...be shure and jam em to start with...and use near max loads...,,wow I sound like a stuk record...but it usuallay works!!!))....Roger

 

[vmthtr]

My 8 twist was a bear to find a light bullet load for. Tried a lot of different powders, seating depths, bullets and primers. Finally got it to shoot very well, but not right away. PacNor 8 twist. It shot the 105 Amax well right out of the box. Built it up after reading the Weekly here.

Mike

 

[chino1969]

Happy to read the above posts as I have a recent Savage/ Krieger 8 twist build that is ho hum with the 105 Bergers but a real MACHINE with the Berger 80's. Got no idea why that's just the way it is.

Hammer,
I have a Kreiger 7.5 twist that was ho hum with the Berger 105's and I contacted Eric Stecker of Berger for advice. I was using 30.2 grn. of Varget with CCI 450 primers with the bullet touching the lands. Eric recommended I start .030 from the lands. I went to the range last night with loaded rounds seated long to shoot at 300 meters along with my seater die and arbor press. I started .030 off the lands and shot a five shot group. I then shot a group of five seated .040 off the lands and shot a .507 group at 300 meters and ran out of rounds. My next trip will continue going further from the lands. Don't be afraid to try going away from the lands to see if your accuracy improves.
Chino69

 

[chino1969]

It looks like a 1:8 twist is the most popular twist for the 6BR as you need a min 1:8 to shoot the heavier 108 g VLD's and everything i have read says this twist wil also handle the lighter bullets.

..But is there any loss of accuracy shooting the lighter 55-75g bullets with this twist?

Cheers


Grant

The only way to know for sure is to try them. All the formulas in the world will not show whether they will shoot in a real world environment. I have a .22-250 AI with a 1 in 8 twist that shoots 50 grn. bullets like a laser beam. Try them and see for yourself. I have a 1 in 7.5 6mm BR that I'm going to try 80 grn. bullets in.
Chino69

 

[joghotrod]

I have a 1/8 twist 6BR,AR) and It shoots the 600 yd F class target accurately. I recently loaded up some 55 gr. Nosler BT's and 2 of the loads shot a little less than 1/2 inch. I haven't been back to the range to see if those loads will do the same or not. But to answer your question, it seems like the 1/8 twist will shoot the lighter bullets fairly well. I will be going back soon to try those loads again and see. My barrel is throated for the 105's, so I had to jump the 55's a bunch. I hope this helps you some.

Jimmy