Sabot sizing - wrap in paper?

[quaid]

Based on my small amount of experience, i believe that 0.507"-0.509" DIA bullet + sabot combinations best fit my barrel. The fitment of the sabot + bullet + barrel also seems to be a critical component of powder combustion and down-range accuracy.

The MMP Orange 458 sabot with a 325gr .458 FTX bullet measures 0.5045 on my calipers. If I wrap the bullet in 1 layer of 0.002 paper, I get a 0.5085 combination.

Has anyone tried this technique for up-sizing loose sabots?

 

[quaid]

For fitment of 458 bullets I also tried the 452x50 MMP HPH 24, which fits too loosely with a 452 to be useful in my barrel. With a 458 these fit quite tightly, and I am certain that the combination results in petals being twisted and damaged during loading.

For me, I don't think using a 458 in an HPH 24 is viable.

 

[bronko220002]

My opinion is that you don't have to be that critical about diameter when using a sabot. If you were to place the bullet/sabot nose first into the bore to check for fit and as long as you were touching the lands you should be good. I'm sure you know this but when firing the skirt of the sabot expands sealing the gasses and engaging the rifling imparting the spin on the bullet/sabot. Once the sabot/bullet leaves the barrel the sabot drops away. Any additional contact with the rifling caused by adding the paper wrap would be causing more drag. I really don't think its necessary.

 

[GM54-120]

My opinion is that you don't have to be that critical about diameter when using a sabot

Its a heck of a lot more critical when using smokeless unless you like missfires or blown sabots. Some Savage book powders ignite easily and some like a much tighter fitting sabot.

 

[bronko220002]

Its a heck of a lot more critical when using smokeless unless you like missfires or blown sabots. Some Savage book powders ignite easily and some like a much tighter fitting sabot.

GM I wasn't referring to the sabot not being tight at the base but up in the petal area where the bullet sets. I agree the base must be snug so it can engage the rifling and form a seal but it doesn't have to be that tight above the base

 

[GM54-120]

Bronko, like i said its FAR more critical with smokeless. I can shoot Lehighs all day with BH209 but take the exact same bullet/sabot with smokeless and it blows/drills the sabot. Change just the bullet to a cup/core and its back to shooting fine again. So yeah bullet to sabot contact matters. Faster you twist it the more grab you need or it shreds sabots.

Smokeless can rise to peak faster and higher so its all important including how much grab the bullet has in the sabot. Its even pretty common for guys to use a Harvester Black Crushrib with a 458 bullet in the Savage MLII just to get a tight fit.

60gr of N120 is good for a little over 2300fps with a 300gr bullet and about 32-34kpsi. You wont get anyhere near that with 120grV of BH209 and a MLII is a 1-24 twist on top of it.

 

[bronko220002]

I don't recall the op saying anything about smokeless but I appreciate your bit of knowledge on that.

 

[GM54-120]

I don't recall the op saying anything about smokeless but I appreciate your bit of knowledge on that.

This is in the smokeless section

 

[ElDiablo]

This guy on YouTube is using foil to achieve what you are describing.

 

[bronko220002]

This is in the smokeless section

OOPS....LOL!

 

[bronko220002]

This guy on YouTube is using foil to achieve what you are describing.

That's an interesting video. I just wonder how long the foil hangs onto the bullet after leaving the muzzle. You sure can't argue the improvement in accuracy he got but I think I would opt for a thicker sabot. One less component to fail.

 

[.45er]

Bronko, like i said its FAR more critical with smokeless. I can shoot Lehighs all day with BH209 but take the exact same bullet/sabot with smokeless and it blows/drills the sabot. Change just the bullet to a cup/core and its back to shooting fine again. So yeah bullet to sabot contact matters. Faster you twist it the more grab you need or it shreds sabots.

Smokeless can rise to peak faster and higher so its all important including how much grab the bullet has in the sabot. Its even pretty common for guys to use a Harvester Black Crushrib with a 458 bullet in the Savage MLII just to get a tight fit.

60gr of N120 is good for a little over 2300fps with a 300gr bullet and about 32-34kpsi. You wont get anyhere near that with 120grV of BH209 and a MLII is a 1-24 twist on top of it.

Don't know about smokeless loads, but I've knurled bullets before putting them in the sabot to tighen-up the bore fit.

 

[GM54-120]

Don't know about smokeless loads, but I've knurled bullets before putting them in the sabot to tighen-up the bore fit.

I have also and sometimes with a huge improvement in accuracy too. Not a fan though of adding stuff like paper or foil. That just creates another variable.

 

[GM54-120]

This guy on YouTube is using foil to achieve what you are describing.

Notice how is is using one of the smallest sabots you can get instead of choosing one that fits correctly. Sounds a bit strange his T/C has .503 lands but a HPH12 sabot should fit that ok.

 

[ElDiablo]

Yes, unnecessary fiddling is my take on it

 

[Salar600]

Hi Quaid,
I do it for years and made a post about that many years ago but seam to be the only one doing this.

I do not use foil or paper tho but Scotch tape and masking tape depending on thickness needed. Scotch tape is .002'' and Masking tape is 004''.

Very easy to fit and to have a uniform layer.

Both material stay on bullet during flight and I would say it does nothing bad because it improve accuracy.

Good luck

 

[Ka'imiloa]

Hi Quaid,
I do it for years and made a post about that many years ago but seam to be the only one doing this.

I do not use foil or paper tho but Scotch tape and masking tape depending on thickness needed. Scotch tape is .002'' and Masking tape is 004''.

Very easy to fit and to have a uniform layer.

Both material stay on bullet during flight and I would say it does nothing bad because it improve accuracy.

Good luck

Interesting point. Millions of bullet were paper-patched in the past to improve bore seal and prevent leading with soft lead bullets, but the trick is to make sure the PP leaves the bullet at the muzzle. I'm sure the famous Henry rifling of the later 1800s, with its "pointy" lands, was designed to cut the paper patch during bore-time, thus insuring its departure at the muzzle. As long as Scotch tape or masking tape stays on the bullet fully during flight, it should be fine, but bullets spin at incredible rates, and thus like to shed what's on them. Velocity, going up and up with inlines, along with ditto for twist rate, thus comes distinctly into play.
Bores are usually nicely finished in inlines, to my evolving knowledge, and thus occurs a mischievous thought that a carefully applied paper-patch (which is usually a two-wrap) to the outside of the sabot should theoretically work OK to boost the bullet/sabot diameter in a pinch, with the "tail"of the PP tucked into the cupped base of the sabot just as in an old time hollow-based bullet. I think the sabot-plus-paper wrap would still work once the usual inline breech pressure was applied, but am steeling myself for replies on this! (Likely an old-hat issue, tho, since I'm an newbie here).
Aloha, Ka'imiloa