Home Forums Hunting & Shooting Ask The Gunwriters Mono bullet jump question-Why?

What exactly is it about mono bullets that makes them so sensitive to COAL when it comes to accuracy?

Is it just because they are copper? Or they need to build up more speed before hitting the lands? Or because they don't slug in the barrel like lead bullets? BTW, Hammer bullets claim they are not as COAL sensitive as others.

As I'm sending downrange multiple 3 shot groups at 98 cents a pop, (making Barnes bullets company very happy with my progress), I'm wondering if it's my powder, primer, COAL, bullet choice or whatever that I need to do to make accuracy possible and what can be done to alleviate us from this fiddling with COAL.

I'm from California, (home of the fruits and nuts), so I'm required to use lead free ammo.

I always use the published Barnes load data including COAL as a start. It's gotten me very close accuracy wise most times.

https://www.barnesbullets.com/load-data/

Having used Barnes almost exclusively for the past 25 years (I am a political refugee of that once great state) IME seat the bullets so the case mouth is even with the first groove and rock on. That as Ghostman said is usually the Barnes recommended COAL.

What I have concluded after using Barnes bullets for over 30 years, as well as several other monolithics, is that some jump probably does tend to help--perhaps due to easier engraving in the rifling.

But haven't found any hard-and-fast rule about seating depth, whether in relationship to the grooves, or distance to the lands. Have found that up to .1 inch jump sometimes results in the best accuracy, whether with Barnes TSX/TTSX/LRX bullets or other makes. So I generally start at .05 inch off the lands (which Barnes recommends) and if the accuracy desired ain't there, seat them deeper.

But have also found this applies to many of the high-BC lead-cored bullets introduced in recent years.

Whatever the reason, it's a PITA and expensive, but when I find the right depth they sure can be accurate.

I've always found (with Barnes, the only monos I've shot) that the Barnes data's recomended COAL will afford good accuracy. I haven't yet, tough, tried any monos in custom cut chambers, only factory rifles, YMMV. As to why they are so sensitive, I offer no advice.

I don't know that I would call them sensitive to sitting dead more than any other. But they do like more jump.

I haven't personally found them to be picky on seating depth. What kind of accuracy are you getting? It may not be a seating depth issue..

[/quote] I haven't personally found them to be picky on seating depth. What kind of accuracy are you getting? It may not be a seating depth issue..[/quote]

Hmm. Have seen MAJOR differences in accuracy after fiddling with seating depth with monolithics, ranging from 3-shot groups of 1-1/2 inches shrinking to half an inch.

John,
Is that with the current crop of monos? The first generation X bullets seemed to be sentitive to seating depth but the TSX and TTSX have always given me at least MOA accuracy once I found the proper charge.

Depends on what level of accuracy you desire. If you're talking MOA for 3-shot groups at 100 yards, that's pretty easy with just about any of today's rifle bullets--though a lot of hunters think that ONE group measuring that much is sufficient. (Jim Carmichel once commented that a lot of "pet loads" are based on a single 3-shot group, which has been my experience as well.)

And I still know some handloading hunters who think 1-1/2 inch 3-shot groups (or one group) is top-notch accuracy. If a big game rifle will actually average 1-1/2 inches for 3 shots at 100, then it will work on medium-sized big game at 500 yards. I know this due to having done it, more than occasionally.

But 5-shot groups are far more indicative of accuracy, because they're closer to the MAXIMUM spread of all shots with that load. Two examples from a recent test I did with the 6.5 PRC for the HODGDON ANNUAL MANUAL show how much:

I eventually found, after trying the various loads they e-mailed me with several bullets, that the 127-grain Barnes LRX and 129-grain Nosler ABLR shot best with Retumbo. Both averaged around an inch for 5-shot groups with the maximum charge listed, with the bullets seated to Hodgdon's overall length.

But I decided to experiment, so seated both .1 inch deeper. The 127 ABLR then averaged .55 inch, and the 129 LRX .71 inch. Again, this is for 5-shot groups, not just 3-shot.

Whether that makes any difference to the average hunter is another question. (Plus, I have also killed deer to elk-sized big game neatly out to 350 yards with handloads that averaged around 2 to 2.5 inches for three shots, using "iron sights.")

But the other thing I learned long ago about both hunting handloaders and the gun-writing business is that MOST readers are obsessed with accuracy, whether it makes any difference or not for their hunting. This is because most hunting handloaders spend far more time handloading and punching paper than actually killing game. Handloading is an addition to their recreation, much like tying flies is to some anglers--who could probably catch just as many fish with store-bought flies.

But to say there's no difference in accuracy with Barnes (or any other bullets) seated at different depths is simply not true.

John, did you test RL26 as well? No Retumbo here, and the LRX is my next project.

No, because the article was for Hodgdon.

But would bet RL-26 work--though haven't played with it yet because have found it more temperature-sensitive than I like, partly due to Montana having the most extreme temperature range of any of the 50 United States. Whether that would apply to your hunting is another question!

Yaddio.... what is the jump range you are currently trying?

My experience has been that they are not as sensitive to seating depth as say a Berger VLD with a secant ogive, but if you are closer than .04 to the lands, it's gonna be tough.

Maybe some specs could help.

What firearm, cartridge, twist, components....etc?

But the other thing I learned long ago about both hunting handloaders and the gun-writing business is that MOST readers are obsessed with accuracy, whether it makes any difference or not for their hunting. This is because most hunting handloaders spend far more time handloading and punching paper than actually killing game. Handloading is an addition to their recreation, much like tying flies is to some anglers--who could probably catch just as many fish with store-bought flies.


Yep!!

That’s me.

One of my brothers was laid up with leukemia. He was bored. I lent him a 64 Winchester 30-30, bullets, powder, and primers. He was as guilty or maybe more so than I regarding having to get accuracy. He worked on that 30-30 for a while and finally told me that he was sorry: “The best I could get was 1 1/2” groups with this thing.”
(He shot 5 shot groups at 100 yards - that was his standard.)
He handed the rifle back to me in a way that I knew he felt that I should probably peddle it.

What I find interesting is the accuracy improvement even in Weatherby throated rifles when seating Barnes bullets deeper. Have 2 different rifles chambered in .257 wby, and groups shrunk in both when Barnes were seated deeper in the case. Talk about a jump!

Same thing here. I have a 7mm Weatherby Magnum rifle with a long throat. The only bullets it will shoot accurately are Barnes. They shoot best when seated deeply. I don't know how much the bullet jump is, but it's a lot, maybe 1/4".

Have seen that several times with Weatherbys, and not just with Barnes bullets but other monolithics. Had a Mark V .270 Weatherby for a while, and decided to try 130-grain Nosler E-Tips.

Since they're pricey I started with 130 Ballistic Tips, which have a very similar ogive, seated so the rounds just fit in the rifle's magazine. Played a little bit with charges of Ramshot Magnum, and the more powder I added, the better they shot. Ended up with 3-shot groups around half an inch.

Switched to the E-Tips, starting the same powder charge and the bullets seated so the rounds just fit in the magazine. Got 3-shot groups around 1-1/2 inches, so started seating them deeper. Groups started shrinking, and ended up around 1/2" with the E-Tips seated .1" deeper than the Ballistic Tips.

Have had similar experiences. While the 286gr NP and 250gr AB both give excellent accuracy (better than MOA) from my 9.3 x 62 at clip magazine length of 3.37" COL, the 320gr Woodleigh consistently gave 2" for three at a hundred at the same COL. I shortened the COL to 3.3" (using 1/2 grain less of RL17) and it shot .40".

Bob
www.bigbores.ca

.

Geez, that's kinda tough to answer. I've loaded monos for .223, .243, .240, .257R, 270 Win, 280, 30-06, 7mm WSM, 300 WBY and 338-06, all with Barnes, some with GMX, E-Tip and also Hammer Bullets. I agree with what MD says about seating depth changing groups, funny thing is there is no standard depth across the board that works in my experience. Ya just have to experiment. All seem to like more jump than lead bullets though. For instance, my Mk V 300 WBY shoots MOA when the 180 TSX is loaded to magazine length. It's still WAY off the lands. I generally start 50 thou off the lands for other calibers and experiment from there. Sometimes I get lucky on the first try, some times it takes 2 or 3 boxes of bullets to get it right. My 257R has been the most picky so far. It's an M77 with a Douglas 1:9 twist. It shot bug hole groups with 100gr Match Kings and H4350 when I got it back from the gunsmith, but with TTSX and GMX bullets I was getting 3-4 inch groups. ??? I finally settled on 100 TTSX and Hunter for groups about an inch, (my buddy just whacked a pig with it a couple of weeks ago). I have a feeling that rifle just does not like monos. So frustrating. I had good luck with Hammer Bullets right out of the box in my 243 and 240 with 55 and 70 grainers, but that could have just been plain luck. I wish I could give you a better answer WB300, but I'm a bit perplexed by monos, hence the original question.