What 7mm-08 load to try?

[roysclockgun]

Scotty I will check MV next week.

Bullet, Sierra recommended 2.800" OAL. I will try what you have recommended. I was going by getting the bullet .005" off the lands and working back. It does seem to like getting a jump into the lands.
Steven in DeLand

 

[SJB358]

Scotty I will check MV next week.

Bullet, Sierra recommended 2.800" OAL. I will try what you have recommended. I was going by getting the bullet .005" off the lands and working back. It does seem to like getting a jump into the lands.
Steven in DeLand

I kinda run by the .020" off the lands for most of the leaded bullets. I think Mike is on the money by backing it off a little more.

Looking forward to seeing what speeds you are getting out of the rifle. Scotty

 

[roysclockgun]

Scotty, is it particular to 7mm-08 that one needs to back off OAL more than usual?
With other calibers that I have loaded for a long time, I am very close to the lands. This like .0005" to .0010" off the lands. With the 7mm-08 I am backing off much farther to try for better groups.
Steven

 

[DrMike]

Bullet composition and construction, and powder and charge. are the primary dictators of "need" to allow for a jump to the lands. Some cartridges, by virtue of pressure maximums, should allow for a jump to the lands. The 7-08 does not inherently demand a jump to the lands, though as is true with any cartridge, may benefit given a particular load.

 

[SJB358]

Scotty, is it particular to 7mm-08 that one needs to back off OAL more than usual?
With other calibers that I have loaded for a long time, I am very close to the lands. This like .0005" to .0010" off the lands. With the 7mm-08 I am backing off much farther to try for better groups.
Steven

I am with Mike, some rifles/bullets are going to want a little more jump. Alot of my rifles don't allow me to get close to the lands, so I load for mag length and haven't found much trouble with the extra jump. I couldn't tell you a thing about the 7-08 really, but my experience is with short magazines for the most part that don't allow for really tuning off the lands. Scotty

 

[DrMike]

I've loaded for quite a few 7mm-08s, and the OAL varies considerably based on rifle, bullet and final velocity of the projectile. I am confident when I say that there is no one OAL that works every time.

 

[bullet]

Hunting bullets like a jump not close to the the lands, and Seirra's recommended OAL for 120 gr bullet is 2.780" and I start at 2.776" with the 120gr BT and work from there. Good luck :mrgreen:

 

[roysclockgun]

Realizing that each rifle is different, in terms of OAL that turns out to be best, I did get this response from the Sierra Tech Team:

"On 12/20/2011 11:01 AM, Paul Box wrote:
> We used an OAL of 2.800" for that one.
> Paul
>
> -----Original Message-----
> From: Sierra [mailto:sierra@sierrabullets.com]
> Sent: Tuesday, December 20, 2011 8:45 AM
> To: Paul Box
> Subject: General question from exteriorballistics.com
>
>
> What is the recommended OAL for the Sierra .284 (7mm) 120gr. bullet with flat base, in the 7mm-08?"

 

[bullet]

Realizing that each rifle is different, in terms of OAL that turns out to be best, I did get this response from the Sierra Tech Team:

"On 12/20/2011 11:01 AM, Paul Box wrote:
> We used an OAL of 2.800" for that one.
> Paul
>
> -----Original Message-----
> From: Sierra [mailto:sierra@sierrabullets.com]
> Sent: Tuesday, December 20, 2011 8:45 AM
> To: Paul Box
> Subject: General question from exteriorballistics.com
>
>
> What is the recommended OAL for the Sierra .284 (7mm) 120gr. bullet with flat base, in the 7mm-08?"

Try what I told you and see, it is the OAL for the exaggerated one hole 20 round group I shot. Of course you can ignore it and not try it, but it just might work for you all so. :grin:

 

[roysclockgun]

I don't ignore anything that I read on here! <8^)) At age 69, I am just beginning to learn things!
Steven

 

[bullet]

I don't ignore anything that I read on here! <8^)) At age 69, I am just beginning to learn things!
Steven

Hey, I am still learning but having a lot of fun doing it. I sure hope you find the load you are looking for, just stay at it and once again, good luck. :grin:

 

[Guest]

Steven, I've had absolutely no significant luck finding loads close to the lands in any hunting rifle I've loaded for, ever. I have had luck finding accurate harmonic nodes at shorter COLs with plenty of jump in every rifle I own, and many others for which I've loaded over the years. I always test magazine length against chamber length to the lands, and start about .020" shorter than the shorter of the two.

I think you're getting there with your loads. It's time to tweak that 4064 loadsnd get it under 1". Oh, and with the hammer forged barrel on that Howa, I'd not be surprised if it just kept getting better over the first couple hundred rounds. Just keep cleaning it back to the bare steel after each range session (20-30rds or so) and you'll get it seasoned in just right.

Keep us posted!

 

[CatskillCrawler]

I have had excellent results using Varget and the 139gr SST in two 7mm-08s. The OAL used for one is 2.790" and the other prefers 2.800. These are both Marlin XS-7s whose serial numbers differ by 12. The difference in accuracy with the diffferent OAL was quite noticeable.

IMR-4064 and IMR-3031 also worked well in these two rifles.

 

[roysclockgun]

Thanks to "bullet" and others who encouraged me to back off the OAL. For years, I have read that getting close to the lands will reap tighter groups. Maybe I was not reading more recent data?

I really do not think that this rifle likes 120gr. bullets. I tried a number of different OAL, propellents, primers and cases.
My old Lyman 47th edition recommended a starting load of 39.1gr. of IMR4064 for the 7mm-08 shooting 120gr. bullets. Remember, I'm working up a light hunting load for my wife. The groups with that load were not great, even when I got down to 2.774 to 2.778" which was the best, shooting ten rounds into a 1 7/8" group. The average MV was 2581fps. This, from a 20" barrel.

The entry level load in a more recent Hodgdon manual was 41gr. IMR4064, so I tried that with the same OAL. The average MV was right at 2700fps. Ten round group measured 1 3/8" with 8 rounds being at 1". I will stick with that load while she is shooting 120gr. bullets. When I switch to her 120gr. Nosler BT hunting bullet, the groups could improve.

I am hoping that she will be able to handle the recoil from a 140AB, as the rifle's 1 in 9 1/2" twist will probably shoot those heavier bullet better.

Any comments or suggestions are always welcomed!
Steven

 

[bullet]

Thanks to "bullet" and others who encouraged me to back off the OAL. For years, I have read that getting close to the lands will reap tighter groups. Maybe I was not reading more recent data?

I really do not think that this rifle likes 120gr. bullets. I tried a number of different OAL, propellents, primers and cases.
My old Lyman 47th edition recommended a starting load of 39.1gr. of IMR4064 for the 7mm-08 shooting 120gr. bullets. Remember, I'm working up a light hunting load for my wife. The groups with that load were not great, even when I got down to 2.774 to 2.778" which was the best, shooting ten rounds into a 1 7/8" group. The average MV was 2581fps. This, from a 20" barrel.

The entry level load in a more recent Hodgdon manual was 41gr. IMR4064, so I tried that with the same OAL. The average MV was right at 2700fps. Ten round group measured 1 3/8" with 8 rounds being at 1". I will stick with that load while she is shooting 120gr. bullets. When I switch to her 120gr. Nosler BT hunting bullet, the groups could improve.

I am hoping that she will be able to handle the recoil from a 140AB, as the rifle's 1 in 9 1/2" twist will probably shoot those heavier bullet better.

Any comments or suggestions are always welcomed!
Steven

Let her practice with the 120 gr bullets and then when hunting use the 140gr AccuBond in front of 47.9grs of W760 using a 2.770" OAL, 210 pirmers and Nosler brass (Winchester or Remington will work but will probably not give you as good accuracy as Nosler brass if you do not turn necks) and you will have awesome groups and she will never notice the recoil (which will only be 15 pounds free recoil with the 140gr bullet, when she shoots any game. Just make sure you sight the rifle back in for her after she practices with the 120gr bullets, and she will never notice the difference when shooting game.