Rifle Boolits Complete Powder Coat or Drive Bands Only

[MUSTANG]

In another thread 405grain posted some ideas on what he termed Hybrid Boolit Powder Coating. See: https://castboolits.gunloads.com/sho...Hybrid-Boolits

In essence powder coating the driving bands only; leaving the nose uncoated. This was an alternative method to completely powder coating the boolits. I tried a few of these and started wondering what the accuracy differential was between fully Powder Coating a rifle boolit – shooting a group and then shooting the same load and boolit with driving bands only coated.


I shot two styles of boolits in a test today; the RCBS 200 Sil and 311290 in my Remington 700 chambered in .308 Winchester. These boolits are on the heavy side for the .308; but I have been shooting a variety of heavy boolits this winter in the .308 Winchester. The following pics show a Completely Powder Coated and a driving bands only powder coat of the RCBS 200 Sil. (Green); And a Completely Powder Coated and a driving bands only powder coated 311290 (Blue).

[MUSTANG]

The following Target is 10 Rounds of RCBS 200 Sil Driving Bands only coated. 1.876 MOA



and then 10 Rounds of RCBS 200 Sil Fully Coated. 3.977 MOA




Driving Bands only had much better group with the RCBS 200 SIL boolit (Gas Checked and 30 Grains BLC2).

[MUSTANG]

The following Target is 8 Rounds of 311290 Driving Bands only coated. 7.502 MOA



and then 10 Rounds of 311290 Fully Coated. 1.749 MOA



Before going to the Range I had expected that one Powder Coating Technique or the other would provide better accuracy. Unfortunately; it’s a head scratcher as the group results between the two techniques on two different boolit styles were inverted.

Anyone else have any similar tests and results with Targets they can share?

[ChristopherO]

Good prep work and research, Mustang. This took some effort and forethought that is quite revealing. I saw that post about putting the pistol case over the nose while coating only the driving bands and it, too, caught my eye. Though I've not hybrid any PC rounds at this stage I do have to double size the NOE 182WFNGC boolit shank and front bank separately to for my 35 Whelen or it is too tight to bolt into the chamber without major effort or skinning the PC off that portion of the boolit. It takes much more handling of the boolit to achieve a good fit in certain applications with cast boolits in general. PC in someway is not any simpler for some designs and chambers/bores, at least in rifles is my experience.

Your results are almost surprising how the different designs swapped accuracy potential based on partial or complete coverage. I say almost because I also find that any little tweaking changes the dynamic of the particular load. This game is not like buying a box of jacketed bullets, finding the right primer and powder charge for the next two decades.
Thanks for taking the time to conduct this experiment. It is really helpful for everyone else that frequents this board and wants to learn.

[mehavey]

As both are bore-riders, does the coated nose of the 311290 have a better/(tighter) fit to the 700's bore diameter ?
OOC: If the 311290 is ALOX'd rather than PC'd -- therefore leaving the nose at original (looser?) dimensions -- are results similar?

As an aside: I'm surprised the PC'd bore-riding section would still chamber

[charlie b]

Were they all shot on the same day and in which order? With no lube on the nose rider portion you may be depositing some lead fouling.

I've tried the partial coat before and had the poor results. Mine was a result of lead in the barrel so I tried coating the bullet with LLA after partial PC. That helped, but, it was more work to me than nose sizing.

I'll just stick to full PC and nose sizing since it gets me 1.5MOA.

But, I also weight sort bullets and sort cases.

[mehavey]

I'll be honest: Bore-rider = oven-dried ALOX for me
PC for most everything else.

[dverna]

Good post Mustang and a head scratcher for sure.

I wonder if you held your tongue differently. LOL

BTW, good on you for shooting 10 shot groups! Most folks are not that disciplined before drawing conclusions.

[Kraschenbirn]

Three or four years ago, I did some similar load development using the RCBS 30-165SIL...with much the same results. My M700 (McGowan barrel - 1-10 twist) grouped measurably better with lubed boolits than PC'd. On the other hand, the Savage M10 (24" fluted factory barrel - 1-10 twist) with its short throat wouldn't chamber that boolit with PC'd nose so I, more or less, dropped the project.

Zoom forward a couple years: Got an Arsenal 309-188PC from Jared, a bore-rider designed and dimensioned for PC, and found that, coated, it shoots better than the lubed RCBS boolit from either rifle.

Bill

[MUSTANG]

Were they all shot on the same day and in which order? With no lube on the nose rider portion you may be depositing some lead fouling.

I've tried the partial coat before and had the poor results. Mine was a result of lead in the barrel so I tried coating the bullet with LLA after partial PC. That helped, but, it was more work to me than nose sizing.

I'll just stick to full PC and nose sizing since it gets me 1.5MOA.

But, I also weight sort bullets and sort cases.

All fired same day. Sequence of 10 Round tests was:

RCBS200 = Bands PC Coated Only.
RCBS200 = Fully PC Coated
311290 = Bands PC Coated Only.
311290 = Fully PC Coated.

NO LUBE on nose of Band PC Coated only Boolits.

[popper]

I tried that experiment few yrs back with marlin 30/30. Result, couldn't see any difference - with my shooting ability. Was using 170 gr RD original mould, some PB others GC. Only thing I did notice was for a soft alloy that slumped, uncovered nose touched bore so it seemed to lead more. At the time I was using HF red and the espc gun. I didn't jam the lands on any loads. Played a lot with uncoated base for PB too - bad. Coated with no GC - bad. Both light unique/2400 loads and hot 4895 loads. Conclusion - for me - tumble PC it with GC on or PB. Testing was done @ 50 as normal range was shut down for couple yrs.

[charlie b]

All fired same day. Sequence of 10 Round tests was:

RCBS200 = Bands PC Coated Only.
RCBS200 = Fully PC Coated
311290 = Bands PC Coated Only.
311290 = Fully PC Coated.

NO LUBE on nose of Band PC Coated only Boolits.

That might explain the groups. First ones through the bore started leaving some lead in the barrel?

[ChristopherO]

That might explain the groups. First ones through the bore started leaving some lead in the barrel?

I wouldn't think that would have anything to do with it. Traditionally the bore riding boolit's long nose won't get lubed in a sizer die, thus being shot without lubing that portion of the projectile, correct?
Plus, with the 311290 fully coated being the last target, and showing a much better group than the 311290 partially coated, if there were a build up of lead in the barrel one would think it would affect the powder coated boolit detrimentally as it could one with an uncoated nose. Some thoughts I gather from this thread, correctly or incorrectly.

[405grain]

Great research MUSTANG. To clarify something: I started calling this a "hybrid" bullet because it is both lubed and powder coated. I've been powder coating the driving bands on bore riding boolits because the nose gets too fat to chamber if I do shake-n-bake on them. I've been either putting a smear of alox on the nose after the cartridges are loaded and letting that dry, or swirl lubing in 45/45/10 and letting that dry, or swirl lubing in liquid paste wax and oven drying. I tried nose sizing after PC, but the nose section wouldn't remain concentric with the driving band section. Most of the testing I've been doing has been with the RCBS 30-165-Sil in .308 bore 7.62x39 bolt actions, and Lyman #311299 as well as the RCBS boolit in 308. On good days I can get around 1.5MOA I'm not able to duplicate MUSTANGS tests because, fully coated, my boolits won't chamber.
Don't get me wrong, I love shake-n-bake, and if it was working for me it would be all I could ask for. The fully powder coated works great on all my pistol boolits, and on 405 grain 45-70 boolits, just not so great on my bore riders. PCing just the driving bands is slow work and for most people won't be worth the extra effort. If what you're doing works, then don't change it. MUSTANGS targets show that hybrid boolits work the same way as other cast boolits: the same boolit can work great in one gun, but not in another. Just like any other cast boolit, you've got to figure out what works best in your gun. If you get better accuracy with fully PC'd or driving band only, then go with the one that works best. At first I wasn't focused on accuracy, I was just trying to find a way to make my bore riders chamber. I know that I could just go back to using lubed boolits, but PCing is just so much more versatile. in example: every 30 caliber mold I have, the boolit can be powder coated and then it becomes perfect for shooting in my 7.65x53 or my SKS. Hybrids aren't going to be for everybody, they're just another tool in the kit.

[Silvercreek Farmer]

Interesting results. Velocity? Have you tried a similar load with those boolits lubed with LLA or a traditional lube?

[charlie b]

I wouldn't think that would have anything to do with it. Traditionally the bore riding boolit's long nose won't get lubed in a sizer die, thus being shot without lubing that portion of the projectile, correct?
Plus, with the 311290 fully coated being the last target, and showing a much better group than the 311290 partially coated, if there were a build up of lead in the barrel one would think it would affect the powder coated boolit detrimentally as it could one with an uncoated nose. Some thoughts I gather from this thread, correctly or incorrectly.

Yep, I looked at the order wrong.

Many people who shoot bore riders will apply something like LLA.

I just know that my long bore riders do really well powder coated, sized body and nose. They are an interference fit in the bore. Just this morning I shot 4" and 7" groups at 500yd. Then 3 of 5 hits on the 6" plate.

BUT...the bullets are sorted to 0.1gn and the cases are also weight sorted (Hornady cases, flash holes drilled). I'd never go back to mixed headstamp cases or mixed weight bullets if I wanted consistent accuracy.

[MUSTANG]

Clarification - In post #14, 405Grain indicates when he PC's the nose of "Bore Riders" They will not chamber. Same for me. This is why I use the Custom Lee .301 Sizing die to size the nose portion of a Full Coated PC boolit; and I also size the body with a standard .310 inch Lee Size die. nose is squeezed back to .301 - I screw the Die only 2 full turns into the top of the RCBS Press; which gives me about the right depth on the PC'd nose.

Follow on to post #15. Still too much snow drifted in front of the firing line to place the Chronograph - So no velocities yet. Also; the reloading shed has the entrance door drifted over so It'll still be a few weeks before I can get the Lyman 450 up and running to Lube some 311290's and RCBS 200 Sil's with Carnuba Red. Comparison of the "Traditional" lube with the two methods of Powder Coating has been on my agenda; but will be delayed until early/mid spring to access the equipment needed.

Next week = Plan is to reshoot the RCBS 200 Sil bands only and the 311290 entirely PC coated (using 30 Grains BLC2). This time I have located the Same Headstamp brass for both loads - previous have all been mixed brass. Over the winter I had taken all of the .308/7.62 brass I had (couple thousand) and sorted into the same headstamps per box of 20 and loaded with Jacketed Bullets for use in the M1a's. This left me only mixed brass available for the shooting I have been doing. But; I have located about 35 pieces of PSU-20 brass that I will be using to see if the Groups shrink with this change - my fear is that the best groups shot today have reached the smallest possible for me given the "Factory Rack Grade" Remington 700, Chinese import Scope, aging eyes, and ....

[MUSTANG]

Just a FYI. The origin of all of these tests posted here and elsewhere was when I wanted to establish some Load Data for boolits using BLC2 as I had a large supply on hand, and to establish some RCBS 200 Sil load data as there is a dearth for that boolit.