Reloading help...

[utah400elk]

I have been reloading for over 13 years and never ran into this before so thought I would look for a little advice.

I am building a elk load for my son’s 7mm-08. it’s a Weatherby Vanguard with a 20 inch barrel and a new VX 3I (thanks again to schmalts for a great price on a Leupold). I am getting 2670 FPS with 140 grn Accubond being pushed by 41 grns Varget. This was the most accurate load with decent velocity.

Now to the dilemma...
I don’t get to the lands and groves until the COL is 2.907. That is a fair bit past the max of 2.800. I was going run a test load at 2.857. Is it just me or does that seem a bit long? I am getting ringt about 1 MOA with 2.800. How much better does anybody think I will get with a longer COL. I have never seated a them that long before. All my other rifles have shot very well at max COL. The 2.857 would still fit in the mag well but not much more.

Thanks for any advice/help.

 

[Fire_9]

I’m assuming you are getting the max case length out of your reloading manual? The lengths in the book pretty much mean nothing to me. I find the lands and go deeper from there. It may shoot better seater further out, it may not...

 

[wseidel]

I have reloaded for years but do not consider myself an expert. That said, I have a similar rifle and will share my experience. I have a Sako Finnlight in 7mm-08 (20 inch barrel) that I hand-loaded with 140 Nosler AB. I also used Varget and ended up with 43.0 grains as my most accurate load with adequate velocity since I would be using this for elk as well (approximately 2740 fps). My COAL is 2.840 and this was close to the maximum of my magazine as I recall. I get a bit under an inch at 100 yards but I've found it is more difficult to shoot a lightweight rifle accurately so I am the limiting factor - not the rifle. One thing that helped me was to keep pressure on the fore-end when shooting from the bench. So, to answer your question about COAL and accuracy...try it at the maximum length that your mag will allow and function test cycling rounds into the chamber to ensure that they feed smoothly. Shoot rounds of varying COALs than your mag maximum and see if you hit a better accuracy node. And, finally, one inch at 100 yards isn't bad accuracy at all. Hope this helps...

 

[Doublecluck]

If it will fit in the mag, the rule is.. as long as it don’t fall out of the case.. lol.

 

[utah400elk]

Thanks Guys. I tried up to 42.5 grns but the group opened up a lot. That got me to 2730 but the 41 grns showed a lot of promise. Just trying to get the most out of this round.
My 257 Weatherby and 300 WSM shot about 1/2-3/4 MOA at max COL. My /sons 7mm-08 is just a tad over MOA and am trying to everything I can to squeeze a little more accuracy out of it.

 

[cahunter805]

As stated above the book “Max” length is just a generic reference usually. Many rifles are limited by the mag box length before coming anywhere near the lands. Other will touch well before you run out of mag box length.
I would load them as long as the mag box allows and will still cycle seeing as you can’t touch the lands in your specific rifle anyhow. Start at max length and work back testing seating depth. You will find that sweet spot soon enough.

 

[SD_Prairie_Goat]

Agreed with what everyone else has said. That max length is guaranteed to work in every gun, but you can go longer to custom fit your gun. As long as it fits in the mag, have at it!

 

[1_pointer]

As long as it fits in the mag comes with a caveat since you worked up a load at a shorter length, just make sure your not into the lands. Generally decreasing distance to lands increases pressure. Since you are not seemingly near max I'd give it a go, but be mindful of looking at pressure signs.

When I work up a load in a new rifle I prefer to start at max mag length or just off the lands, whichever is shorter. This means when I go to adjust seating depth I only have one direction to move.

 

[Brian in Montana]

I'd have to look at my notes but I'm pretty sure my Varget/140gn AB load was at 43.3 gns (not certain at present). My 7-08 is a Rem 700 with a 24 inch barrel but it seems to like a little jump in that bullet. Again, I'd have to look at my notes, but I want to say my COL is around 2.77.

But anyway, 2.857 does seem a little long to me, but it's probably safe. I tend not to go much beyond the SAAMI specs, myself. Usually when working up a load I start at SAAMI max COL or maybe .01 longer. When I find a charge the gun seems to like I'll work on seating depths from there, but generally I don't go deeper than .05 from where I started. That seems to work for me. Compressed loads and COLs way longer than max always make be a little nervous.

 

[N2TRKYS]

I don't chase the lands. I seat my bullets so they'll fit in the magazine. It has worked very well for me.

 

[Deleted member 16014]

Base to ogive will also give you a more consistent reference point than COAL. Obviously COAL matters for mag fit, but BTO is the better metric for reference to the lands.

 

[Gunner46]

Everyone so far seems to be within the sweet spot for Varget & the 140 AB (41.0-43.0, 2750 +/-, 1" groups). OAL is just an individual rifles quirk. As long as your charge doesn't get up past 43.5 gr your still in the safe zone, as long as your not creeping in on the lands.

 

[utah400elk]

Went to the range this morning and both the 2.800 and 2.857 shoot very well. I had a flyer (1/2 inch from touching) with the 2.857. Both rounds are just under MOA. One more range day and we will decide on final hunting round. The 2.800 is clover leaf at 100. The group for the 2.857 was even smaller without the flyer.

Thanks for all the help. The COL is further out of SAAMI specs than I have ever needed to go but very nice shooting rifle for my son. He has an elk tag this year and I am hoping for a deer tag as well.

 

[Laelkhunter]

Don't Weatherbys usually have a lot of free-bore, or is it just their Magnum calibers? I think on some of their rifles, the bullet would be seated really far out of the case to get close to the lands, and still not touch them.

 

[Dougfirtree]

Sounds like you have a good load. But, even 2.8 is relatively long in my experience. I always seem to find my best accuracy somewhere between 2.75-2.775"

 

[Brian in Montana]

I'd have to look at my notes but I'm pretty sure my Varget/140gn AB load was at 43.3 gns (not certain at present). My 7-08 is a Rem 700 with a 24 inch barrel but it seems to like a little jump in that bullet. Again, I'd have to look at my notes, but I want to say my COL is around 2.77.

But anyway, 2.857 does seem a little long to me, but it's probably safe. I tend not to go much beyond the SAAMI specs, myself. Usually when working up a load I start at SAAMI max COL or maybe .01 longer. When I find a charge the gun seems to like I'll work on seating depths from there, but generally I don't go deeper than .05 from where I started. That seems to work for me. Compressed loads and COLs way longer than max always make be a little nervous.

Just wanted to follow up after checking my notes. My powder charge with that bullet is actually 41.3gns. COL was correct. 2.77

 

[std7mag]

SAAMI COAL is a standardization to allow a cartridge to fit in every gun marked with that chambering. In this case the 7mm-08 is based off the 308 case necked down.
Since the 308 family is shot in the AR10 platform also, COAL must be short enough to fit in an AR type magazine (2.80").

This made perfect sense to use a shorter case length to create the Creedmoor line for match shooters using the AR platform.

Most bolt guns don't have the shorter mag restrictions of the AR platform, hence allowing longer COAL.

My Stevens 200 in 7mm-08AI was loaded with 140gr Ballistic Tips to 2.895" (that being 0.020" off the lands) for best accuracy.

Powder charge is not the factor for smallest group size. Powder charge is changed to effect the timing that the bullet leaves the barrel, matching the harmonics.
You ideally want the bullet leaving during the long phase of the harmonics, at the top of the barrel movement. (The bottom is accurate also, but has greater effect on hold over at longer distances).

The bullet seating depth, and cartridge concentricity, affect group sizes.

Laelkhunter,
The Weatherby Magnums do have a long freebore. Roy Weatherby did this to help keep pressures down.
The standard calibers are done with SAAMI spec reamers.

 

[HiMtnHntr]

If you can get a cartridge that is seated close to the lands in your mag, it might be worth fiddling with. However, I would back off the powder charge to near minimum and work up, just as you would any other new load.

I have a Stevens 200 in 08 that out-shoots everything in my safe, especially with bullets seated close to the lands. It has a long mag box that allows longer cartridges.

Other 08s I have with mag limitations, I typically run the standard 2.800.