Target Shooting Loads - The Firearms Forum

merbeau · 12-05-2011, 05:26 PM

Hi

For years I shot primarily handguns in Bullseye matches. I am currently starting to load in a more serious manner for my rifle in hopes of developing a good varmint and target load for my 6mm Super LR. I will be using the Berger 69 grain varmint bullet and their 95 grain VLD target bullet.

During my research I was amazed at the effort rifle loaders go through to make an accurate round. While reading I came across several benchrest articles where the authors mention seating the bullet into the lands. I am a little confused becasue I was under the impression seating the bullet into the lands would cause a pressure increase which could potentially be dangerous.

Am I missing something here or is this common in rifle reloading - the article was on loading the 115 VLD for 6mm cartridges.

JLA · 12-05-2011, 07:27 PM

Yes some rifles like the bullets jammed well into the rifling. you just have to play with it. Keep in mind though that jamming and jumping is only going to fine tune the groups in most cases. The load will usually shoot acceptable with most any reasonable seating depth. i usually develop a load with a .010" off jam seating and then play with it to see if groups open up or tighten. Most cases it has little effect, but some cases have showed to elimate a loads tendency to throw flyers if the bullets are seated a few thousandths closer or further away.

Its just another part of getting to play with your guns.

Bindernut · 12-05-2011, 07:28 PM

Seating on the lands is common in benchrest circles.
They're looking for groups measured in ten thousands of an inch and are trying to eliminate any variation in that miniscule amount of bullet jump and any possible yaw error before it engages the rifling. If the bullet has to jump to the rifling, there is always a variable on how it is going to enter the leade.

Given a fixed powder charge, a load seated onto the lands will generally be higher pressure for the velocity than the same load with the bullet seated off of the lands.
Depending on where your charge is at (min/max/in-between) and what powder you're using the pressure spike can be small or large. When these guys are brewing up their benchrest loads they're not looking for max velocity, they're looking at max accuracy for their particular rifle's barrel which is not necessarily up near the top end where you'll start seeing high pressure.

For my hunting and varmint loads, I prefer to stay back off of the lands by at least 0.025" or more (it depends on each load for each rifle). I shoot year-round with the same loads from +90° to -20°F which already causes enough of a pressure/velocity fluctuation plus I'm wanting as much velocity/energy as I can get.

cpttango30 · 12-05-2011, 08:22 PM

I too stay off the lands .010 to .030".

Caneman · 12-05-2011, 09:32 PM

with these barnes bullets we have to seat them 0.050 off the lands... still group pretty well, though

merbeau · 12-06-2011, 10:52 AM

Thanks to all that replied to my question. The responses have answered my question and it certainly makes sense if one is trying to tweak the most out of the round for accuracy. Again many thanks for respoding.

12-05-2011, 05:26 PM	#1
merbeau V.I.P. Member Join Date: Jul 2010 Posts: 67	Target Shooting Loads Hi For years I shot primarily handguns in Bullseye matches. I am currently starting to load in a more serious manner for my rifle in hopes of developing a good varmint and target load for my 6mm Super LR. I will be using the Berger 69 grain varmint bullet and their 95 grain VLD target bullet. During my research I was amazed at the effort rifle loaders go through to make an accurate round. While reading I came across several benchrest articles where the authors mention seating the bullet into the lands. I am a little confused becasue I was under the impression seating the bullet into the lands would cause a pressure increase which could potentially be dangerous. Am I missing something here or is this common in rifle reloading - the article was on loading the 115 VLD for 6mm cartridges. -->

12-05-2011, 07:27 PM	#2
JLA TFF Moderator/Host Join Date: Feb 2007 Location: Heart Of Texas Contributor Posts: 17,320	Re: Target Shooting Loads Yes some rifles like the bullets jammed well into the rifling. you just have to play with it. Keep in mind though that jamming and jumping is only going to fine tune the groups in most cases. The load will usually shoot acceptable with most any reasonable seating depth. i usually develop a load with a .010" off jam seating and then play with it to see if groups open up or tighten. Most cases it has little effect, but some cases have showed to elimate a loads tendency to throw flyers if the bullets are seated a few thousandths closer or further away. Its just another part of getting to play with your guns. __________________ It takes 43 muscles to frown, 17 to smile, and 3 for proper trigger squeeze. The latest caliber or gear is no substitute for experience and skill. Rifles and cartridges don't make hits -- shooters do. Fact of life: After Monday and Tuesday, even the calendar says WTF!

12-05-2011, 07:28 PM	#3
Bindernut Advanced Senior Member Join Date: Oct 2007 Location: ND, USA Posts: 2,450	Re: Target Shooting Loads Seating on the lands is common in benchrest circles. They're looking for groups measured in ten thousands of an inch and are trying to eliminate any variation in that miniscule amount of bullet jump and any possible yaw error before it engages the rifling. If the bullet has to jump to the rifling, there is always a variable on how it is going to enter the leade. Given a fixed powder charge, a load seated onto the lands will generally be higher pressure for the velocity than the same load with the bullet seated off of the lands. Depending on where your charge is at (min/max/in-between) and what powder you're using the pressure spike can be small or large. When these guys are brewing up their benchrest loads they're not looking for max velocity, they're looking at max accuracy for their particular rifle's barrel which is not necessarily up near the top end where you'll start seeing high pressure. For my hunting and varmint loads, I prefer to stay back off of the lands by at least 0.025" or more (it depends on each load for each rifle). I shoot year-round with the same loads from +90° to -20°F which already causes enough of a pressure/velocity fluctuation plus I'm wanting as much velocity/energy as I can get.

12-05-2011, 08:22 PM	#4
cpttango30 Former Guest Join Date: Jul 2011 Location: Stafford, VA Contributor Posts: 3,071	Re: Target Shooting Loads I too stay off the lands .010 to .030".

12-05-2011, 09:32 PM	#5
Caneman Advanced Senior Member Join Date: Oct 2010 Posts: 1,266	Re: Target Shooting Loads with these barnes bullets we have to seat them 0.050 off the lands... still group pretty well, though

12-06-2011, 10:52 AM	#6
merbeau V.I.P. Member Join Date: Jul 2010 Posts: 67	Re: Target Shooting Loads Thanks to all that replied to my question. The responses have answered my question and it certainly makes sense if one is trying to tweak the most out of the round for accuracy. Again many thanks for respoding.