Nosler's Trophy Grade ammo COL 0.066" shorter than Manual!

[billkieger]

Hi All, the crunch is on in finding that perfect load for my 270(Remington 700) and new Tikka 30-06.

I first sighted in the Tikka two weeks ago. Took 5 shots using Nosler 180gr Trophy Grade ammo, Accubonds(Tikka guarantees sub MOA out of the box with premium ammo (though I did bed the action before I shot it probably voiding that guarantee.) Got lucky!). The rifle was shooting 0.2" MOA. Then shot handloads of different powders(including powder weights ). All shot roughly 1.5" groups. So I started looking at COL. When comparing the COL of the Trophy Grade ammo to the COL in Nosler's reloading manual for the Accubonds (both 165gr and 180gr) I noticed the Trophy Grade bullets are 0.066" shorter than the maximum COL in their reloading manual. Maybe Nosler knows that the Accubonds like to jump? So I am going to try seating the bullets a little further in and see what happens.

Now for the 270. I can not find any Trophy Grade ammo with 140gr Accubonds in the entire state of Colorado to check the COL. I am assuming they too will be loaded shorter. May have to call Nosler to find out what the COL is on their factory 270 140gr ammo.

Are those of you shooting Accubonds finding that they like to jump? Nosler must know something if they are jumping their factory ammo this much. I'm hoping to find a good load without wearing out my barrels. Any suggestions on a COL for the 270? I am not having luck with that rifle either.

And why not just shoot the Nosler factory ammo? Principle

A little background. .
I shoot/load competitively (Service Rifle/AR-15) and typically jump my 75gr bullets 0.03, if I go to 0.06+ I can't hold the 9 ring at 600yrds... I'm relatively new to loading for hunting rifles but I do understand reloading principles. .

Thanks in advance for your feedback.

Bill

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[DrMike]

Bill,

Most bonded-core bullets and all monolithic bullets appear to enjoy a significant jump to the lands. I allow 0.100 inches of jump on almost all cartridges I load with AccuBond bullets. I don't recall any accurate loads that allowed less than 0.070 inches of jump. The only exception that I've encountered for these allowances was the Hornady GMX, which is gilded metal rather than a copper bullet.

 

[Divernhunter]

They need jump just like Barnes bullets and Swift.
I have as much as 1/4" jump in a couple of my rifles and they shoot tiny groups.
Personally I have found a min of .080-.100" jump for best groups.
Try loading them to the factory length and then even shorter.

 

[billkieger]

Bill,

Most bonded-core bullets and all monolithic bullets appear to enjoy a significant jump to the lands. I allow 0.100 inches of jump on almost all cartridges I load with AccuBond bullets. I don't recall any accurate loads that allowed less than 0.070 inches of jump. The only exception that I've encountered for these allowances was the Hornady GMX, which is gilded metal rather than a copper bullet.

Great! That may explain why I can't get the accuracy I'm looking for! Pulled my hair out all last year with my 270, ended up borrowing a rifle for the season. That's part of the reason I bought the Tikka. I've got a bunch I loaded up today, looks like I'll go a little deeper before going to the range.

Is there a rough jump length when seating bullets to the maximum COL in the Nosler Manual? Or are all off the shelf rifles different?

I'm not use to that kind of jump. Assuming I go another 0.066" deeper, will that amount significantly affect pressures? I'm thinking not?

Bill

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[DrMike]

There is a loss of charge volume, but pressure should not be a major factor when seating deeper than cartridge OAL. I routinely start work with all bonded core bullets at 0.100 inches off the lands. On occasions, I may have to allow as much as 0.120 inches of jump, but don't recall ever seating less than 0.070 inches from the lands.

 

[billkieger]

There is a loss of charge volume, but pressure should not be a major factor when seating deeper than cartridge OAL. I routinely start work with all bonded core bullets at 0.100 inches off the lands. On occasions, I may have to allow as much as 0.120 inches of jump, but don't recall ever seating less than 0.070 inches from the lands.

Now you have me curious. Will measure both rifles in the morning and hopefully I'm close to the lands. That way I can go to 0.100" jump and watch my groups shrink, hopefully. ...
Appreciate the help.

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[DrMike]

Consequently, I measure off the ogive to get the COAL. I use a Stoney Point tool (now marketed by Hornady). It allows for greater consistency.

 

[billkieger]

Consequently, I measure off the ogive to get the COAL. I use a Stoney Point tool (now marketed by Hornady). It allows for greater consistency.

On my wish list. Got one for the AR. Will have to do it the old fashioned way tomorrow. Cleaning rod down the barrel trick....

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[DrMike]

That'll do.

 

[billkieger]

Measured the 06, was loading 0.08" off the lands. Will go further.

Wow, for the 270, was loading 0.22" off of the lands using the manuals O.A.C.L of 3.320 for the AccuBond 140. Unfortunately I've got 24 seated bullets, will try moving some out 0.1. This barrel doesn't have to many rounds through it so I doubt it has eroded that much. ..... though that seating depth sounds long. Measured 3.540"..

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[DrMike]

For what its worth, I recall a client's 270 WSM for which I worked up a load. He had requested a bonded core bullet (Scirocco, to be precise). I wound up 0.250 inches off the lands! But it did delivered exceptional accuracy (0.2 inches). Very finicky, but he had put some rather stringent demands on the load he sought.

 

[billkieger]

Ok, I'll try what I have before trying to gradually move the bullets out for the 270 (a PIA).

Going to load up some 06 seated deeper. Will let you know how it goes.

Wish I found this forum many bullets ago. ....



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[billkieger]

Ok, I'll try what I have before trying to gradually move the bullets out for the 270 (a PIA).

Going to load up some 06 seated deeper. Will let you know how it goes.

Wish I found this forum many bullets ago. ....



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[DrMike]

Pleased to have you posting, Bill. There are some very knowledgeable people posting here. They can be a great help. The AccuBond is a great bullet and will deliver exceptional accuracy. They are sensitive to seating depth, however. It turns out that is true for every bonded cored bullet I've worked with over the years. In this, they emulate the requirements imposed by loading pure copper bullets.

 

[TackDriver284]

My .300 Win Mag has a .010" jump with the 180 AccuBond, it depends on the rifle though. I hear the Barnes, and copper bullets likes more jump. Most of the guys here has been happy with a longer jump with their AB and ABLR bullets.

 

[billkieger]

My .300 Win Mag has a .010" jump with the 180 AccuBond, it depends on the rifle though. I hear the Barnes, and copper bullets likes more jump. Most of the guys here has been happy with a longer jump with their AB and ABLR bullets.

Got the 270 dialed in for the first time in over a year! Only shot 3 or 4 (if I didn't chronograph it) shot groups. As lots have said on this forum, H4831SC works great! Jumping 0.22(Nosler Manual COL, got lucky). Tried H4350 at different jumps and powder weights but couldn't get under 1". Best 3 shot group with 4831 was with 58.5gr(2901fps). Absolutely no pressure signs. Now I'll clean the gun and try again with more shots though tempted to try for a little more speed?..............

06, still got work to do.

Bill

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[DrMike]

Good to see things sorting out for you. This may be a good load, but it still takes a rifleman to deliver the goods. Congratulations all the way around.