I had an issue with H4350 availability but had a ton of IMR-4350 on hand. I searched and searched fot 6XC load data with 105+gr bullets but found exactly nothing. So I looked at 6CM and 6x47L data and burn speed, bulk density and energy content and made an educated guess. My guess worked better than I’d hoped.
The load below was safe in my rifle. Your mileage may vary. Start at least 2 grains lower and work up.
Case: Norma LRP
Bullet: 115gr DTAC
Primer: Federal 210
MV: 3050 avg
Barrel: 25.5″ Columbia River Arms 3-land polygonal
I see the question asked constantly about IMR-4350 vs H4350. Nobody ever has the answer for IMR4350, they just say, “go get H4350.” but that’s both glib and unhelpful. With an identical load of H4350 I get 2980fps with similar SD’s and an identical POI. Group size with both powders was identical, 5 shots into half an inch, 10 shots into 3/4″ from a bench.
Yes, H4350 is more temp stable but sometimes you just have to run what you brung. I personally think IMR-4350 might be a better choice for those that shoot in relatively stable environmental conditions (so most of us). Velocity is higher without any more sign of pressure than H4350 (I’m sure there is a little more but not enough to say grace over).
If you can’t figure out how much of a particular powder to use, sometimes you just have to use your head and a little judgement about your head’s abilities to make good judgements and, when appropriate, give it a go. I know that will run afoul of the sensibilities of a lot of people but you have to understand that modern BOLT ACTION guns are so ridiculously strong that you’re unlikely to damage the gun itself with a small error in burn rate, energy content or charge weight. Semi-automatic platforms are very different and you can damage them substantially with a lot less of an error. In modern bolt aaction rifles it’s when the errors in burn rate, energy density or charge weight get really big that things come unglued suddenly. The line between safe and actually dangerous for a bolt action rifle is a lot wider than most people think. The line between within the pressure limits of brass cases is much narrower but that’s mitigated by all the safety elements designed in to rifles like gas venting ports.
Now you have the information anyway. IMR-4350 is a great powder choice for 6XC and other fast 6mm’s like 6x47L and 6CM with bullets from mid-weight to heavy for caliber. Don’t let the me too’s on web forums cock block you from reaching your goal. If you like. IMR4350, it’ll work just fine. In a case with ~40gr powder capacity, you should come down 2 grains from your H4350 load and work up.
As always with my load data, this is information not advice. You are responsible for your actions and your safety. I provided data as an EXAMPLE of what can/will happen. It’s not a prediction or your results and you should exercise reasonable amounts of caution.
This is a delicious, crunchity, creamy, sweet, chocolate-y packet of amazeballs. You’ll just have to hate me for being right after you try it.
Take one of these:
Then pull it apart.
Then get some Tillamook medium cheddar cheese and commit a crime against humanity.
Be sure you have sufficient ratios of ingredients.
OMG this is so yummy. I originally did it in an attempt to ruin someone on Oreo cookies and/or cheddar cheese. Not only did it backfire in the most interesting way but said individual was more put off by a very tiny glitter bomb.
In the end I was left with a new confection and not much more.
Insert “cool starry bra” jpg’s and pictures of your horrendous feet in the comments below.
Thanks to my good friend KVK and user TurboF for pointing out some embarrassing errors so I could fix them. That comes as a patched minor version update. Version 10.5 is a patch release with fixes for MV, Secondary Data and other very minor tweaks. This is not a significant update but you might as well upgrade anyway. It’s free, right! Click the link below to download.
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This little case seems to really like being as full as possible and/or run a little hard and put away a little bit wet if you get my meaning. We broke in the barrel with 15 shots but as you can see from the data below, around shot #6 things stabilized. By round 10 I had warmed up the barrel a bit and was vacillating between baking rounds in the chamber while I wiggled around trying to get a natural point of aim and firing quickly when I was already at a good NPoA.
All discussions of load data and charge weights come with the “don’t copy me and hurt yourself” disclaimer. Don’t just run my loads, work up to them. These are all on Norma brass, F210 primers, 115gn DTAC bullets and COAL at 2.8″.
After grinding out the first 15 rounds to break in the bore and establish a zero; this was a BRAND NEW barrel after all, we took a little break and went to check the target. The new barrel shot to such a different POI than the prior barrel that it took quite a few shots just to get on steel at 100yrds. By round 10 we were on steel at what seemed like pretty close to POI=POA. Enough to move to the BoxToBench Precision 100yrd Load Development Target and dialed the zero in on the cold zero aiming point. 5 rounds at the cold zero put us at 15 shots and we were already seeing each set of 2 bullet holes (because: adjust, fire 2, adjust) either touching or very close to it. We’re pretty excited about the performance we’re seeing so far.
After the first 15 shots and letting the gun cool down I settled in to go for groups for record. Starting off we did the Coach’s match load (CML) which is 38.5gn of H4350. Then the RL-23 was run followed by N550 and IMR-4166. To wrap things up we came back to the H4350 and did the 39.5gn load then finished out our paper punching with 5 at 39 grains. After that I had 5 rounds left and wanted to drop a shot on the 900 yard target so we went up there and I rang the gong for 5 rounds of 38.5gn. There’s a called flyer (obvious) on 4 of the 6 aiming points. I wasn’t in the most stable position and I knew it.
My velocities are a solid 150fps above what Coach gets from his Enfield rifled barrel of the same length with the same load. Ok, to be completely transparent, it’s not EXACTLY the same load. We do actually seat the bullets about .120 deeper forn my new barrel than Coach’s barrel but I can’t see 150fps difference from that. This is the polygonal rifling in full effect. Less friction because you’re not engraving the bullet, you’re swaging then and then twizzlering them, if only ever so slightly.
So now on to the powder results. H4350 you see the curves change shape as you fill the case up. To my eye it almost looks like someone’s grabbed on to the right side and started pulling the string taut. Group sizes went down as powder charges went up but we’re talking about going from a .75″ group to a .71″ group to a .3″ group. The academic in me is crying out to be let loose with a scale and all of my reloading supplies to do a 1/10th grain at a time experiment. But, that’s expensive and I have other matters to attend to. The experienced rifle shooter in me says, “You do realize that any one of those is sufficient for the 1000yrd stuff you’re doing right?” The competitive rifle shooter in me says, “Take the 39.5 and let’s go home and load ammo before you change your mind again.”
Onward and upward. We still have loads to analyze. Everyone knows that after my experience with it in .243AI and 6.5x55AU that I’m a big fan of Reloader 23. It’s sloooooooow burning and has been returning impressive velocities with reasonable pressures from very heavy for caliber bullets in relatively long bores from very overbore cases… as you would expect it to do if you are at all familiar with Boyle’s Gas Law. We had no idea how much to start with so we did exactly what Coach did with it for my .243AI. We filled the case up to the body:shoulder junction, dumped it out and weighed it and put that much into 5 cases. It came out at 38 grains with no drop tube, just a funnel and a weighing pan.
Reloader 23 showed me with my .243AI that it likes a full case (I’m sensing a trend here with these slow burning magnum powders) and that it’s pretty hard to put enough into a 6mm case based on a .473 case head to blow the damned thing up if you’re seating to SAAMI/CIP lengths. 38 grains produced pretty nice velocity. A testament to the efficiency of the 6XC case setup. Still with 28fps SD’s, 66fps ES and a .68″ group of 5, it would “do” but I’d want to develop it more if I were to use it. We did find that RL-23 is a great option. Somewhere around 40 grains should give high 2900’s at reasonable pressures even when seating bullets deepish.
Pressing on, we have N550. A double base NG/NC powder known for being a little temperature touchy after 90F and for being pretty darned expensive. 36.5 grains of N550 gave us a nice narrow 11.95fps SD’s on ES’s of only 29fps. Still a little tall but velocities were touching 2900 and pressures were VERY low. It also grouped a .2″ group of 5 shots. Oh man am I tempted to increase my powder budget by 25%. We figure we could fill the case on this stuff somewhere around 39 grains at 3,000fps. But, I don’t want to develop a load; much less an expensive one, if one jumps out at me and that H4350 load at 39.5 grains is hard to beat even with stupid tight groups.
Now we cross into “Coach style load” territory. So far we’ve been on the very slow side of the slow side of the rifle powder spectrum. Now we’re going to cross the street where the Beatles fans turn into Stones fans and start dragging their knuckles. Not really. Just making fun of coach. The defining line between a “Me” style and a “Coach” style of handload is I like my powder to burn all the way down the barrel giving consistent pressure all the way without a huge spike of pressure in the case itself. My way is easier on brass but harder on barrel throats because there’s more grit coming out of the case neck this way. Coach likes his pressure to form in the case, for all the combustion events to happen in that space and then to use the built up pressure. He also tends to jam bullets rather than jump them where I jump them at least a little bit normally.
Making a Coach style recipe means you know you’ll see pressure sooner or later in your experimenting. That being the case and the fact that there was no data for IMR-4166 (which is around Varget/IMR-4895 burn speed) we elected to hot-foot bloody educated guess it. I calculated that 37.5 grains was about the most we’d want to try and so we tried that. It came back hot enough to imprint my ejector hole on the brass so that’s at least 1 full grain too much juice. It did however make 3080fps with a 2fps SD and a 6fps ES for 5 rounds. Drop a grain or two and you’re right up around 2950-3000fps. What a smoker though! Too bad the pressures were simply too high.
Below you can see the velocities as they came out of the gun during testing. You can see it took about 5 rounds to season the bore and then it’s pretty much standard load development wavy gravy until you get to 2 very specific sections whose extreme flatness gives away that something very cool happened there and needed to be paid attention to.
So while N550 turned in the best group and ok SD’s, the extremely tight SD’s and the super tight group out of the 39.5gn load of H4350 has won the day. I might mess with bullet jump a little but really, I’m happy. Best not to waste barrel life.
On the topic of barrel life. Common wisdom is somewhere north of 1500 rounds but under 2000 before it’s smoked. Well that’s about a year and a half or 2 worth of life. That’s from a conventional Enfield rifled gun. I run Columbia River Arms polygonally rifled barrels which have been giving me very long barrel life and I used only HBN coated bullets for the last 1000 rounds (it’s at north of 1300 rounds now).
My .243AI still runs like a laser. I only took it off because seating depth was longer than my magazine, but there’s plenty of bullet still in the case yet. I could take it another 500+ rounds if I was willing to single feed. Pushing 115’s at 3200 can’t have been gentle on it and the expectation was that by 1000 rounds it was going to look like 5 miles of rough road down the bore but it’s not. It’s smooth as glass still and makes tiny 1000 yard groups. So if we take this barrel life thing to mean the point at which the boat tail is up inside the neck of a loaded case when seated equals cooked, my .243AI will have gotten something like 2000 rounds before its death. Thanks to some combination of the HBN coating and the polygonal rifling.
Well then, I expect something like 4,000 rounds of life from my 6XC and something like 6,000 rounds from Coach’s since we’re giving his the Modern Sparts Systems Accuracy Oil treatment for its whole life. If I pull 4,000 rounds out of this barrel I’ll be surprised as hell. 3,000 rounds wouldn’t go amiss though and would be well representative of my real expectations.
Numbers don’t lie so if you want to see those numbers, scroll down and check ’em out.
Definitely seeing a velocity boost evolving during the treatment phase. Looks like SD’s are growing but we won’t know the long term trends on this for another week as there are more shots to fire. Treatment phase is 5 sets of 5 shot groups. Between each group we apply a very light coat of MSS Accuracy Oil down the bore on a patch wrapped around a brush. That pulls the carbon out pretty well and puts another layer of their crazy effective lubricating oil down the bore.
This test data shows 50 rounds of history gathered during bench-rested zero-checking, load development and grouping data collected over the last year with me not cleaning the bore at all on my heavily customized, Columbia River Arms barreled Mossberg MVP .223 followed by another 25 rounds of very recent history from last weekend’s testing with MSS’s cleaning system being used.
Avoiding much discussion of velocities we can look at group sizes. This rifle with this load has been a pretty consistent 1-1.5MOA rifle. It doesn’t like this load, never has, and that has annoyed me because it should be a killer load. During the testing and doing the Accuracy Oil re-application treatments I saw very consistently that the first shot was wild, then the 2nd-5th shots gradually closed in on each other finally ending with shots 4-5 stacking on top of each other. Overall group sizes started at 1.2MOA and by the end of the initial Accuracy Oil treatment plan had reduced to a very nice group under .7MOA with the last 3 shots touching and the first 2 just slightly off that cluster (could have been shooter error but I doubt it). This behavior was consistent from the first string to the 5th string. I have not cleaned the barrel after shooting. I did run a patch down the bore with Accuracy Oil on it though. Before shooting next time we’ll run a few dry patches down the pipe to make sure it’s completely dry and then we’ll see what happens.
Each string below represents a 5-shot set with statistics reported for the string. This load has slowly evolved over the last couple years with a little OAL and a little powder being added between string 1 and string 9. I stopped messing with the load spec after string 9 because I just wasn’t shooting the gun. Now I’m sticking with that practice while we finish up our testing. 75 rounds in to the testing we’re seeing definitely trend line activity but we’ll save the analysis and conclusion drawing until we have more data.
So what do you think? Will this trend continue? Will it even out? Will it reverse? We shall see.
Note: This is not one of my match loads. This is a load I never shoot in competition because it’s not been consistent enough. I’ve wanted to do a little more work on it because it’s a really mild load with long legs. I chose this load because it’s not a one-holer out of the gate so we have some room to see if MSS’s claims are worth taking seriously. So far, they’re at least intriguing.
Do you know what a standard deviation is? If not, start with the Wikipedia entry on that then come back. The document above is rife with terminology from statistics. If you don’t understand the really quite simple definitions though you’ll probably miss the point.
What the document above says in short is that, all else being equal, a cold-bore shot on an animate or static man sized target beyond 700 yards is more or less a pipe dream. In fact, a first round hit even by a highly qualified shooter beyond 400 yards on a man sized target starts to get to less than 99% certainty of impact of metal anywhere on meat.
In a continuation of our re-launch from the close call earlier this year, we’re launching our new logo. This new logo will begin adorning the website and all new versions of BallisticXLR, BallisticPRS, BallisticRexLR and our latest product being announced separately. Big thanks to my ever present partner in crime Wouter for crafting this killer logo.