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

That was my question as well and the speculation that it may not be a seating depth issue at all.. OP did not respond. There's a lot more to getting great accuracy/precision than pushing the bullet in and out of the case.. OCW, neck tension, case volume, TIR and keeping everything consistent plays a bigger role in precision, but some guys/gun writers want to jump right in and say its a seating depth issue. OP is a little vague and we do need a little more specifics..

BSA, we may have crossed posts. I tried to elaborate a little better on the previous page. I'll try to sum it up with a couple of extreme examples: My 300 Weatherby was extremely easy to get 180 TSX's to shoot accurately. I seated bullets to magazine length, loaded up some RL22 and bam, shot lights out. Just luck? Maybe. My 257R was another story. Hard luck here. I tried different brands of brass, sorted brass for concentricity, tried multiple seating depths and charges of powder, primers, tried what is commonly accurate powders in the 257R, ie IMR4350, H4350, RL19, Hunter, etc and mostly had terrible accuracy with monos. The 257R is a Ruger M77 action, Douglas 1:9 SS barrel, Boyd's stock free floated and glass bedded topped with a Leupold VX-2 3x9 scope so I don't question the gear and eliminated the above factors. I know this 257R is a shooter cuz it will shoot lead bullets very accurately with those same powders and 100 grain bullets. Like I posted earlier, I finally did get the 257R to shoot just under an inch @ 100 by fiddling with seating depth and the right powder, but this was after a LOT of shooting off the bench. These are two extremes, most of my rifles fall in between these two extremes and with a little bit of experimentation can be made accurate enough for hunting. Usually I'll try a mono with 2 or 3 likely powders, narrow it down to one powder, play around with seating depth for best accuracy and lock it down. I've concluded that seating depth does have an impact on monos, much more so than lead bullets, so my original question was why is this so? I didn't mean to make a big deal out of this question, was just curious if there was a simple answer.
Good shooting,
Yaddio

I talked with a few of the bullet maker engineering types and they said that given the metal is harder on the outside it’s more difficult to evenly deform…

Which means it has to have some jump otherwise any mis alignment will make it shoot worse… and that comes from multiple factors….

Makes sense if that's what they said, but isn't that contrary to loading lead bullets close to the lands or even kissing the lands to enter the lands straighter and reduce deforming?

I have my doubts about how much the engineering types "know" either. Look at the history of the Barnes product line, they are on the fifth generation now...I'm all about adapting to change, but it seems it is more trial and error than engineering.
Yaddio..pm sent.

I do this, too, since I read about it on here and it has worked like a charm so far.

Not really - the other bullets are soft enough that they can touch and still engrave equally fairly often…..

BUT - you also have to factor in kiss the lands came from the time when they were putting 8-15 thousands of clearance between the brass and chamber and the lands are 6-8 thousands tall…. So getting help aligning them was good…

Today they don’t put that much slop in.

with the 7 STW with 120 and 140g TTSX, 7 Mag with 140g TTSX all shoot sub 1/2" and less jumping .050...I have never changed to another seating depth! Lucky Me!

I want to try the 80g TTSX in my 243 AI and 243.

Were you starting .050 off of the lands as Barnes suggests?

Pretty sure that's where they say to start anyway.

My first time trying. 243 80 grain TTSX in a 243 I was seating 3 at .030 off, 3 at .050 off and 3 at .070 off.

All 3 of the three shot groups were between 1/2 & 3/4".

Exactly.

The reasoning for seating lead-cored bullets close to the lands originated back in the day when many hunting rifles were military surplus, especially the couple of decades after WWII, when millions of 1903 Springfields, 98 Mausers and Lee-Enfields were sold so cheaply that many were converted to sporters, in varying degrees. Because they were military rifles, the chambers AND chamber throats were cut generously, to allow ammo to feed, shoot and the empties extract in the dirtiest conditions.

This meant that for handloaded bullets to stay reasonable straight as they entered the rifling, they needed to be seated close to it. Otherwise they could tilt considerably. This technique/assumption is still being passed down by many handloaders, and some manuals.

Today's target and even hunting rifle throats are much closer to bullet diameter, often just about exactly bullet diameter. Thus bullets CAN'T tilt as much before entering the lands, and don't have to be seated close to the lands to shoot accurately. Due to various factors they may shoot more accurately when seated .1 inch or more from the lands--and often do.

The other factor is that despite this progress in chamber "precision," quite a few factory rifles are still chambered slightly off-center--which can be seen with a bore-scope: The lands on one side of the throat will be slightly longer than on the other side. But this doesn't mean the rifle won't shoot well.

I have owned (and still own) rifles with factory barrels like this group under 1/2" at 100 yards, and not just for 3-shot groups but 5-shot groups. And despite how many handloaders believe in 3-shot groups, 5-shot groups tend to average about 1.5 times larger. This is because groups don't reflect a rifle's CONSISTENT accuracy until around 6-7 shots are fired--due to that dreaded subject statistics. Similarly, 4-shot groups from the same rifle and load will average about 1.33 times the size of 3-shot groups--but around .8 times the size of 5-shot groups.

But yes, monolithic bullets are enough harder than MOST (but not all) lead-cored bullets to affect how well they engrave in the rifling--especially if the rifling's a little longer on one side of the throat than the other. But many of today's high-BC lead-cored bullets are also affected in the same way, due to longer ogives--one reason "steeper" ogive bullets often shoot better when seated closer to the lands, and why extremely long tangential ogives vary more in their "accuracy" seating depth.

Thank you John for that explanation. It really explains things well in a way a simple mind like mine can comprehend.

Reading through most of this I can't disagree with many statements. In short I usually end up about .0050 off the lands and then and am happy with that accuracy. after all I'm using these on game not Target though I'm sure they are capable of Target accuracy from what some of my gun shoot at that.
But in thinking of this I don't know but I have ever tried Barnes or any other monolithic in a 5R type barrel. Or any other pentagonal rifling..

Oh yea, I've tried different seating depths IAW Barnes suggestions. I'm not new to them. I've had good luck with little load develpment with them at times and hair pulling frustration at other times.

Thanks for jumping in with this JB!

Sakoluvr,

Thanks!

But might also mention the accuracy-increasing effects of shorter, tighter chamber throats have been known for a LONG time--even for "military rifles."

Earlier this year I acquired a Griffin & Howe customized 1903 Springfield, which many custom-rifle fans still consider one of of the finest ever made. During my research (which of course included shooting the rifle, which I plan to hunt with this fall) I discovered that during the heyday of the G&H Springfields they were often made on National Match barreled actions, purchased directly from Springfield Armory. And during much of the G&H 1903 heyday of the l1920s and 1930s, Col Townsend Whelen was the commanding officer there.

He would often personally select barreled actions for G&H to use--partly because the "Howe" of Griffin & Howe was James Howe, who had been the head toolmaker/gunsmith at Frankford Arsenal when Whelen was head of research & development there in the early 1920s. In fact Whelen apparently personally selected the National Match barreled action for Ernest Hemingway's G&H Springfield, which was delivered to Hemingway in mid-1930--and was his favorite hunting rifle for the rest of his life.

Anyway, while starting to handload for and shoot my rifle (which is in excellent condition, from the barrel to wood) I discovered the chamber throat was shorter than any other .30-06 I've owned--including my New Ultra Light Arms Model 24, which typically have minimum SAAMI-spec chambers. But this G&H had an even shorter throat--and with some research I found this was typical of National Match 1903s--which of course were not made for combat conditions. (My rifle, by the way, was also made in 1930, a few months after Hemingway's.)

There's also plenty of information about this sort of stuff in the biography of famous barrel-maker/gunsmiths Harry Pope, who experimented considerably not just with barrel-making techniques but chambers and throating. (He graduated from the Massachusetts Institute of Technology, so was definitely not a guesser.)

I too thank you for your inputs on these crazy at times posts MD. I'm glad you've hung in here while other gun writers dropped out.

Interesting subject about barrels. I've at times wondered about barrels that could be made to increase performance with monos. Twist rates are already increasing for long, heavy for caliber cartridges and this trend certainly helps when shooting mono bullets with heavier bullets. But barrels being made with chambers or rifle throats being closer to bullet diameter could be another trend. When re-barreling a couple rifles I was tempted to call Barnes and ask if they've noticed any manufacturers barrels working better than others with their copper bullets. I never did call.

I love having a 1:8 twist on my .223 Tikka T3 when shooting heavier mono bullets for coyotes. The 36 and 40 grainers seem kinda light for that, but I've got confidence shooting the 50 grainers, whether TTSX or VG.

Anyway, I feel that more and more states will go non-lead in hunting bullets in the coming years and if the rifle/barrel manufacturers are smart they'll jump on this trend and cater better to the mono bullet shooting crowd.

Yaddio, An idle mind is the devil's playground and you mentioned "rifle throats being closer to bullet diameter". That is where my latest experiment is kinda/sorta going. Being reluctant to alter the throat (no taking that back once it's done) last evening I took some Barnes TSX's chucked them in the lathe and turned down the nose to the first cannelure to a diameter to match the true bore diameter of the test rifle. This is nothing new of course, bore riders, Loverin style, JD Jones, SSK, even old George Schoyen had good results with bore riders...all I'm doing is experimenting in copper instead of lead. Going on a big family campout the week of the 4th, but will test them when I get back...I'll let you know if I see any success.

I can't wait to hear your results flintlocke. Have fun on your vacation.

Hammer Hunter Bullets claim that their bullets are not sensitive to COAL when it comes to accuracy. They claim this on their website. Their construction is different from TTSX, GMX and E-Tip. They're patented I believe. I've only loaded them in 243 Win and 240 Wby, both with outstanding results. 55 grains for the 243 and 70 grains for the 240. In neither case did I need to fiddle around with COAL. I just worked up trying 3 different powders in the 243 all with good results and only one powder for the 240. Could be dumb luck, I don't know. I'd have to shoot them a whole lot more in a lot more calibers to conclusively decide that they aren't sensitive to COAL when it comes to accuracy, but they may be on to something.