Effect of Powder Coating on bullet velocity

[Tomme boy]

21gr of 5744 and a 215gr bullet is my do all load in my Mosin. It does not leave ANY unburned powder in the bore. Maybe the extra length has something to do with it. My ES was 9 with this load. I was also using WLP primers. The load really came around when I switched to that. It will shoot right at 1" at 100yds. Less than 1/2" at 50yds. But the main limiter is the 2x pistol scope I have on it. And my bad eyes from being a diabetic. They change as the day goes on. Sometimes worse, sometimes better.

Even in 308W I never had the unburned powder. Just like everything else shooting cast, what works for one does not for others.

 

[Snakeoil]

Whoa, talk about 6 degrees of separation...

First, Ian, rifle is an 03, not an 03A3. It is a 4 groove barrel made in 1921, original to the rifle. The slug I pushed thru the bore yesterday measures 0.311. I will ask others at the club what their slugged results were. We have several with NRA sporters and National Match 03 rifles with star gauged barrels.

The 6 degree comment comes from the drawings from NOE. I spent a chunk of the day (in spite of the warm temps) looking at bullet drawings on both NOE and Accurate sites, in search of a 311284 bullet. I found the 311-221-RN and send an email to NOE asking if it was indeed a copy of the Lyman bullet.

Spindrift, I understand the importance of BC. Which is why the Accurate mold site was a bit disappointing with only FN type bullets shown. I asked if they made a replica of the Lyman. You can't insult my intelligence. I challenge you to find it, first. Although I have to warn you, I'm not just another pretty face.

All seriousness aside, what I am is ignorant on this subject. I've been shooting, and a lot of it competitively since I was about 14. But many of the other disciplines lend zero knowledge to rifle shooting and the black magic of cast bullet rifle shooting. I'm not a total newbie to rifle shooting. But accuracy from smokeless propelled cast bullets at semi-extreme yardages is a new challenge for me and learning new things is one of the true spices of life.

I am fortunate to be within striking distance of Maplewood Bullets. Ed casts bullets by hand for customers and offers the Lyman bullet. I sent an email to him about this today and it's a nice day trip type ride to go over there to pick up a 100 or so bullets for testing purposes. Hope to hear from him shortly.

I found my can of 4227. Smells okay. Bit of rust inside the can. I think I used some of this when I first got my Springfield. I kinda remember telling the guys at the club about clouds of red dust as I poured the powder into my measure. I apparentely dumped out the contents and weighed it. Written on the with a Sharpie is 298 gr. So that's how much 4227 is left in the can, and that includes the unknown amount of iron oxide. So, would iron oxide be a deterrent or an accelerant?

Wow!!! That's one big mutha of an imoge.

 

[Ian]

Did you use a dead-soft lead slug for measuring the groove diameter? Calipers or micrometer? I'm still having a hard time getting my head wrapped around an '06 with a 31-caliber barrel. Have you ever cast the chamber to see what kind of throat it has and what the throat entrance diameter is?

I ask all this because powder-coated bullets prefer not to be too far oversized, while lubricated cast can be as large as the rifle will chamber.

 

[RicinYakima]

Historical reference. In 1942 Ordinance allow Remington to go up to .302" bore and .310" groove. Replacement barrels after about July 1943 were allowed an additional .001" on both. Mainly because Remington barrels were cut rifled while High Standard (read Smith Corona) barrel were button rifled and could hold .300" and .308" plus one. By the end of 1943, 03A3's were training rifles mostly, so they were not critically inspected. Remington was broke by July 1944 and were allowed to make spare parts for the money they had received prior to bolt action production stopping in March of 1944. They survived 1945 and 1946 by "rebuilding" new and used 03A3's (bringing them up to specifications) before going into War Reserve. FWIW

 

[RBHarter]

Rick that certainly explains volumes about why the 03A3 I had in nearly unfired condition marked Rem 11/43 on the barrel wouldn't talk to me . It is the only rifle I've ever had that I spent that much time working the mechanics and that many loads looking looking for something under 4-6" with no success . I did find a gallery load that would shoot about 2" but unique was still leaving unburned flakes in the barrel . I hope it's new home has the right tool or the right whatever to make it sing . Last I saw of it it was on it's 4th Reno show vendor .

 

[RicinYakima]

RB, I once had a Remington barrel, two groove, with one groove a thousandth deeper than the other one. I had worked with this for a few months and finally made a bore cast. The casting would "bounce" as it rolled across the bench top so just found it by accident. Things made in WWII were not as well made as we are lead to believe. My Father's first Liberty Ship out of New York for Halifax still had a team of welders inside stitching the ship together. Luckily, they picked up a load of wheat for England rather than tanks so didn't break apart in the North Atlantic. Ric

 

[Snakeoil]

Just slugged the barrel again and did it twice. Ran the slug for the entire length of the barrel. 0.311 plus or minus 0.0001. I made a new slug for this. It came out just like the one I did the other day.

Talked to the guys at the club today. Seems I'm the only one who has slugged his barrel. Also talked to the resident gunsmith, builder and vintage guru. He said he's slugged many and most run in the 0.308-0.309 range. But when I told him mine slugged at 0.311, he was not surprised. Bore looks great and shoots well. My issues with occasional flyers is not the rifle.

I also mentioned the comments here about 2400 being position sensitive. I got some of the strangest looks I've ever gotten. None of the guys shooting Springfields with reduce loads and 2400 have ever experienced any inconsistency when the conditions are perfect.

I also double-checked with my shooting partner about the wild 2400-2500 fps he got with 2400 and that PC bullet that started this thread. He took out his phone and showed me the actual results. SD was huge, close to 100. Load was 16 gr of 2400. He uses a Harrel's measure and has a digital readout (think that is what he said) on it to boot.

 

[Snakeoil]

Tom at Accurate and Ed at Maplewood both replied. Accurate makes a copy of the 311284 Lyman bullet, but with a flat nose.

Ed said he can cast some of the same bullets for me and sell them as-cast. But his mold drops them at 0.310. So, might ask him to make them a bit on the soft side. He only wants $18 for 100 bullets. Not sure I'd be willing to cast 100 bullets for $18.

 

[462]

.

 

[Ian]

Ok, so make your powder-coated bullets .312" or so. The pc coating needs a compressuon fit in the barrel, but not excessively so. I found the minimum limit to be half a thousandth over groove in my .458 Socom, when I ran the unchecked bullets at groove diameter they got badly gas cut and hit the 25 yard target paper fully sideways.

2400 (or any powder) will reflect its position-sensitivity if you locate it in different parts of the case for each shot in a string. I you single-load the cartridges with the rifle sitting in bags and chamber the cartridge the same way every time, you could get the impression that the powder doesn't care, but that isn't true.

 

[fiver]

if you really wanna see it go weird use a pistol primer and throw the cases in there however you want.

I bet you have to up over 19grs to get the accuracy back.

 

[Tomme boy]

Your wild spreads in velocity show that you are having ignition problems. Throw some dacron in the exact same load and see what happens.

 

[Snakeoil]

Ian, you don;'t mention what kind of velocity/load your are using that resulted in the severe gas cutting. Are these reduced loads or hot?

The poor ignition thing is probably more of an inconsistent pressure thing due to the slippery nature of the PC bullet based upon what I"ve learned here. I say this because the identical load with a regular cast bullet shoots well. Maybe if I seated the bullet further out to engrave things might improve. We have quite a few of the PC bullets left. But I probably will not experiment further with them unless I run out of stuff to do. And we'll probably have to use Steve's rifle since my barrel is probably too big for the PC bullets we have. Plus there is no gas check on them so any further work may just be a waste of powder.

We generally shoot off the bench, one at a time, or offhand, one at a time. This is all match shooting. I'm no longer a hunter so all my reloading is intended for match shooting. This thread was started primarily to understand why those PC bullets shot so poorly compared to standard cast. At some point I might venture into PC bullets. But for now, good old standard cast and lubed bullets will do.

This was a good conversation and I truly appreciate the input from everyone.

 

[Ian]

Probably lots of reasons why they shot so poorly. The main point I try to make to anyone shooting PC bullets is to throw away what you think you know about loading techniques for cast bullets and start learning anew because the coating requires its own approach. RicinYakima did something similar, just taking some coated bullets and loading/shooting them like normal and his first results were pretty dismal. A few of us posted some suggestions and he made some changes that turned in some acceptable groups in the end. Not match groups, but he made significant improvements in short order. We see this a lot. Maybe I need to write an article on the subject to outline the basics of what has been working for me and get people thinking in the right mode when they decide to try PC'd bullets in their rifles.

The 458 Socom load was 1K fps, 500-grain Lee gas check bullet without the check. I was using Longshot powder to get the velocity I needed and burn curve to reliably function my AR-15. The pressure was bumping near max for the platform, I estimated around 35K psi peak based on Quickload and chronograph data for four different powders in which all but one powder tracked actual velocity right with the predictions withing a few FPS. The Longshot load would keep five inside 2" at 100 yards with coarse, plastic aperture sights.

 

[popper]

Average velocity was 1603 fps with SD at 44 fps. Extreme spread was 166 fps One of the problems in investigation different lubes, coatings, etc. That ES number obscures any difference. Overlapping bell curves. IMHO, I don't really care which is faster. I get the terminal performance and accuracy, fps I want and am satisfied.
First attempt,several years ago. AR10 308W - prone on freezing ground (so was I) with first use of bipod @ ~60 yds - PC & H4895. 2400 fps. 'C' marked were ones I know I pulled. I would expect different results from a 2 groove vs 5-6 groove barrel. Oh these were a l.g. bullet - 165gr GCd. Spray PCd with HF red, sized 310. I get same results with NO l.g. (but a very small DISPLACEMENT groove), tumble PCd. That load did MOA @ 200 on steel (and knocked down the swinger). My latest BO mould is 145gr GC and has NO groove - displacement is in the GC shank and that works fine. Still a 'groove' left after PC and sizing.

 

[fiver]

hey Ian.
go back and read that PM we had with JW.

 

[Ian]

That was a good one, wish he'd posted in public instead so we could reference it.

@JWFilips , if you read this, how about we pull the whole PM and stick it here, or post a public thread where Fiver and I can copy/paste our responses to it?

 

[fiver]

I happened to get to thinking about changing up the powder speed with the P/C bullets because of the slippery.
as you know it has been on my mind some recently.

 

[Snakeoil]

Not bad groups. I assume the "C" rounds were "called" flyers. But 50 yd groups don't really tell you too much from my perspective. 200 yds on the other hand says quite a bit and MOA at 200 is normally a good I indicator of what the load will do at longer yardages in my limited experience.

 

[Ian]

Here are some of my PC loads, for reference:

5.56x45 NATO: NOE 68 grain TC bullet, enough H335 or IMR 3031 for 2900 fps.
300 AAC Blackout: Lee 452-230 5R, enough RX-7 for 1030 fps and reliable cycling with the long, carbine-length AR-15 gas system.
30-30 Winchester subsonic: Lee 311-120 2R, just a pinch of Titegroup and a large pistol primer, 950 fps.
30-30 Winchester: ACE 140, enough RX-7 for 2300 fps from 20".
.308 Winchester subsonic. Lee 309-230 5R, enough Titegroup for 1000 fps. Can't make up my mind if CCI 200 or WLP shoot better.
.308 Winchester factory ammo duplicate: MP 30-180 Silhouette Hollow Point, enough RX-7 for 2550 fps from 22" barrel in gas auto.
.308 Winchester: Lee C312-155 Ed Harris bullet, IMR 4320 for 2250 fps from 22" gas auto.
.35 Remington: Lee 358-200 RF, enough H335 for 2200 fps.
.38 Special: Lee 358-125 RF, Speer #11 medium load of 473AA.
.45 ACP: Lee TL452-230 TC, seated to 1.208" for function in all guns, 875 fps load of Hodgdon Universal.
.45 Colt: Accurate 45-255C, or 45-297G, each with an SAA max load of Bullseye.
458 Socom: Lee C457-500 RF, no gas check, enough Longshot for 1000 fps.

All of these are accurate, effective, and work fine cast from exactly the same alloy which is "modern", sorted clip-on wheelweights with 2% tin added, and all bullets air-cooled from the powder coating oven. I have tried the 5.56 loads water-quenched and aged from the coating oven at 18-19 BHN but my rifle couldn't tell the difference. I water-down the MP .30 Silhouette alloy with about 10% soft lead and then oven quench them back to 14-15 bhn, but that gets me from 2 MOA groups to 1.5 MOA for ten on any given day and slightly better mushrooming and weight retention, though it has turned in a variety of 5/8-3/4" 5-shot groups at 100 yards. 13 bhn is the minimum for accuracy in the LR-308.

Actually writing down and listing these loads which I use the most makes me have a really funny realization. Powder coating allows me to steer away from the cabinet full of expensive, custom moulds from a multitude of individual and group buy sources and rely on mostly Lee moulds, Titegroup, and Reloder 7.