Maximum copper jump to lands in 270?

[Obi Wan Reloadi]

Good evening, all,

I'm struggling to find the right jump to the lands in my copper 130gr 270 load. Currently 70 thou, at 70% max powder load. The grouping is okay, but not great - I don't want to seat the bullet closer to the lands because of pressure issues with copper.

I'm wondering if I should seat the bullet deeper? What is the maximum distance to lands you would consider safe?

Thanks. Obi.

 

[troy fairweather]

Don't most copper bullet makers recommend 50 thou,

 

[stringnut]

As troy said maybe a bit closer to the lands. Also what powder are you running at 70% of max? Many powders don’t burn very consistent when loaded down too far. If you are running something slow, or any ball powder, that low I cannot imagine it working all that well.

 

[JDeere]

20 off for my most accurate .270 loads in my old model 700. Bug holes all day with 130gr Nosler BTs. The problem you run into is magazine length for hunting rifles with bullets like the BT. You may have to find a happy spot in order to fit the magazine.

 

[AJC1]

If you want a quality test. I recommend the berger seating depth test on their site. Barnes used to say .050 jump don't know if it does any more. A seating depth test normally follows an ocw test, and pressure is not a problem unless your trying to use the "node at max or above" most charges don't go down to 70% unless your talking about case fill of a fast for chambering powder.

 

[JFrank]

I’m not familiar with the copper bullets or why there would be a pressure issue in the first place but I’m sure I don’t want the bullets pressure ring below the neck shoulder junction either. Are these a secant ogive, tangent ogive, or a hybrid of some type ?

 

[Obi Wan Reloadi]

Thanks, chaps - I'm sorry I left out the most important details!

It's 130gr Hornady CX.

RL19. The manual gives a range from 52.9 to 59.4 - I'm at 57.5 gr with no pressure signs.

EDIT - speed just less than 3000fps according to the Hornady manual.

Nowhere near fouling the magazine.

Do we think I should increase the charge closer to max and get closer to the lands then?

Hi, @JFrank . As I understand it, with copper the reason not to get to close to the lands is because copper doesn't flow as quickly as lead when it hits the rifling and this can cause a pressure spike.

 

[Okie_Poke]

I don’t have any experience with the cx bullet, and only a little experience with other copper bullets, so take this advice for what little it’s worth. But I would probably keep going on the powder charge and leave the seating depth alone for now.

I wrote into Barnes asking for load data on their 168 TTSX and Reloder 16 powder once. They answered my question and then included an additional bit about seating depth. I kept the email. The Barnes rep recommended doing a seating depth test starting at 0.050” off the lands and working further back from there in 0.025” increments and to not be scared of getting 0.150” or 0.200” off the lands if needed to find the sweet spot or if necessary because of a long throat or magazine length restrictions.

I know you’re not using a Barnes bullet, but I wouldn’t be scared of keeping a .070” jump if the seating depth otherwise “makes sense” in relation to any magazine length restrictions, how long the throat in your rifle is, and how far into the case the bullet is seated.

 

[IWAC]

Thanks, chaps - I'm sorry I left out the most important details!

It's 130gr Hornady CX.

RL19. The manual gives a range from 52.9 to 59.4 - I'm at 57.5 gr with no pressure signs.
Do we think I should increase the charge closer to max and get closer to the lands then?
Hi, @JFrank . As I understand it, with copper the reason not to get to close to the lands is because copper doesn't flow as quickly as lead when it hits the rifling and this can cause a pressure spike.

 

[IWAC]

Is the Hornady CX a plated or jacketed bullet?

What COL does Hornady recommend? You do have, and have read a reloading manual or three, haven't you? The manual's COL is a safe starting point, with rifles that haven't been shot a lot, or "improved", but people use everything from just touching the rifling to really wide. As long as they fit the magazine, usually good to go.

Just remember a human hair is about .003", so, little tiny adjustments are probably not really useful. Personally, I think .010" at a time is fine. Your load is "high center" of Hornady's recommended, and not Max. No pressure signs is good!

Only change one thing at a time, otherwise, you will be confused.
Change bullets...Nosler, Speer, Sierra, and Hornady... all offer supremely accurate bullets in their "everyday, plain vanilla, good enough for 99% of us" bullets, and they don't cost as much as the super whiz-bang premium ones, either.
Plated copper bullets aren't as hard as Jacketed ones, And Jacketed data can usually be safely used for plated bullets.
ACCURACY? People have spent years chasing the last "gnat's nut" (don't ask how i know this)of accuracy, but in this day and age, that can get EXPEN$IVE, not to mention creating hate and discontent! Except for Benchrest shooters, 1 1/2" at 100 yds. is plenty for game out to ~3-400 yards, which is a FAAAR piece! A careful reloader should be able to better that figure, and if not...SO What? An animal won't care, if shot well!
GOOD LUCK!

 

[Varminterror]

20 off for my most accurate .270 loads in my old model 700. Bug holes all day with 130gr Nosler BTs.

NBT's aren't monometal bullets.

 

[Varminterror]

I've never met a copper solid in any sub-33cal cartridge which didn't like 50-80thou jump.

In my first instances trying monometals, I quickly gave up hope that they'd shoot well, largely because I was loading them under the same premise as lead core bullets. There were actually a few years where I swore off monometals for any purpose until another shooter handed me the key - Jump at least 50k, not 5k, and life is easy.

(Bonus note: I've also found this to be a very beneficial premise for loading segmented core bullets like Swift A-frames and Nosler Partitions as well).

 

[Hugger-4641]

Is the Hornady CX a plated or jacketed bullet?

CX is a solid copper.

 

[IWAC]

CX is a solid copper.

Thanx! I obviously didn't realize that.

 

[Thomasss]

I'm struggling to find the right jump to the lands in my copper 130gr 270 load. Currently 70 thou, at 70% max powder load. The grouping is okay, but not great - I don't want to seat the bullet closer to the lands because of pressure issues with copper.

I tell you right now. It don't work that way. You say you are off 70 thou. 70 thou. off of what? Many guns are different even from same Mfr.
Give us all the info. you can. Mfr. gun name, age of gun, where you think the lands are; what your measurement actually is.
NEXT: if it were me. I would drop down to 54 grains and find the place of the best POI and then do a ladder test and slowly come back to your max. load. IT'S A LOT SAFER THAT WAY.
NEXT Are you aware that if you really want to shoot 130 grain size bullet in copper, you need to increase bullet by one size to get equivalent in copper from where lead would go and how good a lead bullet would mushroom? So you really want to shoot a 130 grain copper?
Finally as easy way to find out the lands is to take a fire case and inset a bullet into the case as far out as it will go and stay in the case. The bullet should be a little tight in the case. Measure that distance and write down on a piece of paper. Also measure the amount that the bullet is sticking out of the case. Then hold the bullet just over the flame of a candle and allow the soot to turn the bullet black. Then gentle as possible, slowly chamber the round by closing the bold. Now open the bolt and allow the bullet and cartridge out. If the bullets sticks bounce the gun but on the ground and see if the bullet will come out. You may have to push it out from the muzzle with a wood dowel or cleaning rod. Now carefully measure the bullet to the point where you see the soot stopped from being rubbed. Or put the bullet back in the case where it was originally and measure the distance frlom the bottom of the rub to the bottom of the fired case and that is the distance to the lands. Your bullet will go into the lands to some degree before the contact is made. Now you have to decide how far off the lands you want your bullet to be off the lands. And ask us for recommendations. You can also figure of where the 70th thou is from where you think you started. I would try this method several times and see how bullets come out with the same measure to the lands. Use a different bullet each time for more accurate measurements. And let us know what you find.
For your info, I have two Win Model 70 in .270 Win. for my sons. One likes a 130 grain Core-Lokt at 3.248" and the other likes it at 3.295." And each time you change bullet size and type you get to do this all over again.

 

[Okie_Poke]

If you want a quality test. I recommend the berger seating depth test on their site. Barnes used to say .050 jump don't know if it does any more. A seating depth test normally follows an ocw test, and pressure is not a problem unless your trying to use the "node at max or above" most charges don't go down to 70% unless your talking about case fill of a fast for chambering powder.

I know I've read that test at some point in time, but I had forgotten about it. They have two of these tests: one for their VLD and one for their Hybrid bullet shapes. Both make a lot of sense to me for, at least for non-competitive purposes.

 

[AJC1]

I know I've read that test at some point in time, but I had forgotten about it. They have two of these tests: one for their VLD and one for their Hybrid bullet shapes. Both make a lot of sense to me for, at least for non-competitive purposes.

It's the only systematic test I know....

 

[Varminterror]

I tell you right now. It don't work that way. You say you are off 70 thou. 70 thou. off of what? Many guns are different even from same Mfr.
Give us all the info. you can. Mfr. gun name, age of gun, where you think the lands are; what your measurement actually is.

"I tell you right now..." It do work that way...

70 thou off of the lands is 70 thou off of the lands. Bullets care a lot more about jump to lands, regardless of manufacturer or age of gun (WTH?) than any of the nonsense which followed.