Cast Bullet Heresy: Seating a Cast Bullet Into the

[Maven]

Over the years, we've all read how a cast bullet seated long enough to be marked by the rifling centers it and improves accuracy. I've followed that advice since I began casting and reloading in the 1980's. However, I've also found that in some rifles, it made no difference, e.g., in my Marlin .45-70 (#336, Microgroove rifling). With the same load and range, seating a CB long enough to be marked by the rifling vs. seating to 2.55"OAL made no difference at all with respect to accuracy and was easier to chamber to boot. (Btw, if you want to load a full 70gr. FFg black powder, you'll have to go longer, e.g., 2.64" in my rifle and single load them.)

This was driven home to me again today when I was shooting Saeco #315 @ .311" in my .30-06 (Mod. 70 Win.) at 3.30" (into the lands) vs. 3.24". Using 48.5gr. and 48gr. WC 860 +WLR mag. primers, I got larger groups usually with a flyer with the 3.30" OAL, but at 3.24" it was one large hole @ 50 yd. with unweighed milsurp cases (1x fired, salvaged from our range bbl.) and unweighed CB's. As said earlier, the longer length didn't perform as well until I tapped 13 of the deeper into the case with a brass hammer. Things then improved dramatically; i.e. with different, yet still unweighed brass and #315's my [13 shot] group approximated that of the first 20 shot 3.24" unweighed milsurp brass group.

Sometimes it's good to question the conventional wisdom!

 

[Rick H]

I have never loaded long enough for bullets to be marked by the lands. (well, at least not on purpose) Perhaps I am giving up a bit but I am pretty satisfied with the results I have been getting without it.

 

[Spindrift]

Sometimes it's good to question the conventional wisdom!

Indeed, it is!
When I started bullet casting some years ago, I also believed minimal jump/jam fit was the key. There are some bullets that will maybe work best like this. But a bullet with self-aligning properties will usually benefit from a little jump. By giving the bullet a little room to wiggle to center, you reduce the detrimental effects of less-than-perfect cartridges and chambers.

Another statement of conventional wisdom, is you can’t seat the bullet with the gas check below the neck

 

[462]

Another statement of conventional wisdom, is you can’t seat the bullet with the gas check below the neck

My two Swiss K31s were not smart enough to know about that.

 

[CZ93X62]

All of my rifles are much smarter than I am, so I listen closely to what they tell me. My handguns are miscreants, and love nothing more than giving me Bronx cheers and rude gestures. They are a recalcitrant rabble, a malevolent mob. Never ask them a question, or seek directions from that lot. You never know where you'll end up. I just keep them fed, and behavioral issues are minimized.

 

[Ian]

Most conventional wisdom got me conventional results. I didn't want conventional results, so I had to find what worked better.

 

[JWFilips]

For me: I start all my loads seated tight into the lands or Throat depending on the style of bullet.
This way I know I'm safe with the load especially if I back the bullet off ( but I seldom do for target work)
Granted I will not extract a round once it is chambered! But I'm only shooting paper and if I get the "all clear" I say "hot" and fire it

 

[MW65]

My two Swiss K31s were not smart enough to know about that.

Neither does my Savage 99...

 

[CWLONGSHOT]

All of my rifles are much smarter than I am, so I listen closely to what they tell me. My handguns are miscreants, and love nothing more than giving me Bronx cheers and rude gestures. They are a recalcitrant rabble, a malevolent mob. Never ask them a question, or seek directions from that lot. You never know where you'll end up. I just keep them fed, and behavioral issues are minimized.

SO SO TRUE!!!

I also was always told and did seat into or to kiss rifling with cast. Untill I cannot for some reason. Like a PC bore rider thats just too "fat".


The big drawback is as a hunting cartridge. More often then not that cartridge thats in the chamber WILL NOT be fired and needs be extracted. Occasionally... That bullet becomes attached leaving a messy action...

cw

 

[dale2242]

I loaded some Saeco 145gr bullets in my grand daughters 7MM-08.
They were seated hard into the rifling and shot ragged holes at 50 yds.
The problem was the bolt closed hard and it was hard to extract an unfired round.
I didn`t want her to deal with that but also did not want to lose that kind of accuracy.
I seated the bulled deep enough so they rounds would chamber and loaded rounds would extract easily expecting the groups to open up.
Much to my surprise and delight they did not.
BTW, when the bullets were seated out the nose portion of the bullet was deeply engraved with the rifling.
Bullets were sized .284.

 

[Missionary]

Oh the joys of experimenting and trying just because we can.
Then enter a reamer to take that abrupt "bump" off the edge of the rifling.
No more curbside service.. have to get out and walk up to the window to get the strawberry shake.

 

[JonB]

well, just call me "conventional wisdom"...at least up to today. Next time I am searching for a resolution to a rifle accuracy issue, I'll be trying a jump.

 

[Dusty Bannister]

Interesting thread about seating depth, but I see only the OP mentions the powder to suggest a relative burn rate, and is the alloy not a factor? Does a soft alloy need the support at the time of ignition? Does the very slow powder benefit from the bullet starting resistance into the lands, or does the reduced resistance by allowing a "running start" have an affect on the burn rate. Or does the burn rate even matter?

Does any of this matter if the purpose is match accuracy or just hunting accuracy?

 

[CWLONGSHOT]

Ooh it ALL matters. (All makes a difference) But to me the real questions to what degree...

cw

 

[Dusty Bannister]

And that is the purpose of my question. If it makes a difference, is it actually the amount of jump or are there other unstated conditions that add to or subtract from the result. So the question remains, what ELSE is involved?

 

[Maven]

Dusty, I use WC 860, not because it's the best CB propellant, but because it was cheap and I have a lot of it. Normally I'd use something like H/IMR 4198, WC 820 (AA #9), AA 5744, and most often lately, Unique. As for the alloy, I'm not fastidious about concocting it, but I imagine it is close to WW + 1% Sn: bore leading is virtually unknown in my long guns with that alloy. Lastly, my results also apply to my .243Win. (Ruger #1), where I use the 87gr. Ly. Loverin CB, but most certainly not with WC 860. Btw, long ago gun writer Jim Carmichael found he could seat the 87gr. Loverin as short as 2.29" and still get damned accurate results (Handloader article in their archives). I tried it and he was right.

 

[Dusty Bannister]

The collection of articles in The Art of Bullet Casting offers a lot of different methods which included seating off the lands, and sizing to groove diameter and not larger. Only the really obsessed will expend the maximum effort for those rumored one hole groups. I am not wired to seek that sort of thing, but I do find it interesting that so many will offer a result, but not enough fact to see if there is any common factor or factors that will result in modest improved accuracy. As CW says "it all matters" I was just commenting that perhaps some have thoughts what is their key factors.

Some would be maximum efforts, others would be practical efforts.

 

[waco]

Ooh it ALL matters. (All makes a difference) But to me the real questions to what degree...

cw

It only matters if it does.

 

[Maven]

Does the very slow powder benefit from the bullet starting resistance into the lands, or does the reduced resistance by allowing a "running start" have an affect on the burn rate. Or does the burn rate even matter?

Dusty, I've used a lot of slow burning powders over the years, e.g., WC 860 and the even slower, chunky IMR 5010, but neither of them was really affected by bullet/land engagement. What mattered more was [cast] bullet weight (heavier was better) and whether or not I used a filler, such as Grex, spherical shot buffer, or powdered bran (recommended by Jay Downs/Aladdin long ago I think on the Boolets site).

 

[popper]

According to Pressure Trace and QL, jamming the lands with jacketed can increase pressure 5-10k psi. 5k psi is assumed the start pressure so burn rate increases and pressure rise. Heavier hammer? Assume also that the nose is partially aligned in the rifling I assume distortion is reduced. I did find bore riding (not engraving) increased accuracy without the bullet touching the bore entrance - so alignment helps even though bullet is not engraved. That was for Marlin 30/30 but my autoloader AR10 doesn't seem to care - not bore riders or even touching the seat. So - only matters when it does.