Trail Boss 308 project

[Tertle]

I recently picked up a Sportco Omark .308 with a barrel that had not seen much use but was sadly a little pitted from neglect.

I thought that it would an ideal rifle to learn how to reload with my first set of caste projectiles that i have made from scratch. I’ve been fortunate to have a cast bullet Yoda to help me, one that wears purple long johns, but that’s a another story!

My aim was to make a suppressed .308 with a very low noise signature, for a couple of reasons, to save my hearing, as a bit of a challenge, to plink with and also to see if i could make a humane hunting round.

I spent the last few days tinking with some load development and thought that i should post the results, hopefully they will help someone doing a similar project.
Please be aware i am rather new to this caste loading so please bear with me and my terminology. Also i am lacking in a Chrono and as such cant get too technical with speed or variations, but will happily take any positive comments or criticisms

As to the load, I opted for Trail Boss for the powder, as it had the recommendation of a local gunsmith and it had some characteristics i liked, one being it would be hard to double charge the powder load in a case.

I casted a 200 grain projectile (sorry i am not sure of the exact mold from what it came from) that i sized to 309 310 and 312 and gas checked (home made too with the help of my Caste Boolit Yoda!)

My first set of loads started at 9, 10 and 11 gr of Trail Boss. Unfortunately I initially seated the projectiles in way too deep, whilst the accuracy at 50 meters was good, at 100 i just couldn’t get it to hold any degree of reliable accuracy. I tried variations of flaring the mouth or sizing it partially with a 303 sizing die. It gave somewhat ok but unreliable results, in other words the groups were ****. Then late last night when i was in bed trying to sleep, I had a slight epiphany, the neck of the case was sizing the projectile and interfering with the bands on the projectile, i needed to get those bands onto the lands.

Well today i went down to the range, i seated the round to expose the second band and made a test dummy round, i then chambered the test round & when i ejected it i saw good engraving marks.

I then made up a test batch with 10 grains, .309 sized projectiles, i full length resized case and used CCi LR primers, debured flash whole and did the primer pocket etc etc.

Fired a fouling shot and went on to fire 3 rounds, was very happy, made up a batch of 5 rounds and fired them but using .310 sized, as the photos show, went to ****, fired a further 3 sized at .309 and things went back to tight and sub inch. the black dots i use for target are an inch.

My next step will be to weigh the projectiles, scrap any poor finished or looking ones, weigh brass etc and after some good advice will resize the projectiles in a far gentler fashion, and chrono the rounds.

But so far i am very pleased with the results

[x101airborne]

Right on, man!! Those are good groups. I have been interested in a sub sonic load because buying Lapua sub rounds is getting expensive! You have given me some really helpful ideas. BTW: I like that boolit! Can you find out what it is? Maybe ask Yoda? I tried using the force, but it hasn't had coffee yet.

[sav300]

cast bullet engineering? Looks like that purple long john design.

[acemedic13]

I vaguely remember a hunting photo a man in NZ donned in some purple long johns......Awesome boolit and great info. I have been playing with this very same idea for a quiet load in my 30-30. Looks like I gotta get some trail boss.

[W.R.Buchanan]

Lyman 311299. Try seating the bullets so the top driving band is exposed and the case is crimped in the top groove. You need a good crimp on these.

I personally don't like the smell of Trailboss,, my .02.

However it works fine and you can't hardly do anything wrong with it. There is a pamphlet you can get from the MFG that has a zillion loads for just about everything in it. Handloader Magazine has covered it in several articles too.

Here's a pic of a .30-06 case with the same bullet showing the proper? place to seat it. Note the roll crimp which I did with the seating die, as a second op after the bullet was seated. The crimp is necessary as it gives the charge time to build pressure before the case releases the bullet, Kind of like pressurizing your cheeks before you hit them from both sides to spray the cottage cheese.

Same holds true for the .308. However when seated this way it may be too long to feed from your magazine so you would have to single load. If you seat it deeper the gas check is below the case neck and might not survive the firing process.

Here's a rule that covers all bullets/boolits::: If you screw up the base of the bullet in any way it WILL NOT FLY STRAIT! You can pretty much carve this in stone.

This means if you gouge it while seating it,,, if the gas check is not on strait, if the charge melts the base, whatever. Accuracy degrades rapidly depending on the amount of damage to the base, kinda like falling off a cliff.

The design of this bullet (311299) is such that when properly seated as shown above,,, the driving bands, lube and GC, are all inside the case neck. Nothing hanging out, thus protecting the base from degradation. Also putting a gas check on a bullet with an incomplete base will not fix it.

Also you don't want the bullet burried in the rifling as that will spike pressure. It may not be a problem with Trailboss powder but it will be a problem with regular rifle powders. So don't make a habit of doing it.


The three bullets shown below are what I shoot in .30 cal rifles left is Lachmiller .30-173 FPGC same as Lyman 311314, 2. Lyman 311299GC, and Lee 309190GC

You can see that both of the FP bullets are shorter in the nose. The one on the left is for .30-30 and may hang below the neck on a .308, however the Lee boolit will work just fine seated correctly in the .308 case. something to think about when you need another mould. The Lee mould I have is 30 years old and makes perfect Boolits every time.

Hope some of this helps. CRIMP CRIMP!

Randy

[prs]

Don't forget to use an internal size die appropriate for the given diameter of lead boolit.

prs

[NHlever]

While the home made gas checks are fine, and work well, you have to remember that the gas checks do not crimp on like the Hornady checks do wich means that some can stay on, and some can fall off in flight. ( I suspect this is happening since the groups are so much better at 50 m than at 100m.) You also have to be doubly careful that the check is not seated below the neck in the case, or in the powder space. The last thing you want is a loose gas check floating around in there where it doesn't belong. I would shake all your empty cases (I'm assuming .303 Brittish) to make sure there isn't a check left in there for some reason. The .303 should be a good cartridge to work with on this project since the powder capacity isn't too huge, and it has a reasonable case neck length.

[Tertle]

Hey thanks guys for the input, xAirborne, I will make enquiries with Yoda and get back to you, yeah I’m trying to keep my costs down too, the most expensive part so far is the primer, but so far in total its well under 7cents a round all up :)

NHlever, i think that my issue was possibly the amount of bullet jump and seating of the projectile, could be wrong but when i seated the projectile as close and into the lands that i could, the 100 meter groups were 1/3 of what they were at 100 in some cases? However could it be that if the projectile is somewhat out of alignment as the base enters the barrel that the gas check gets knocked? to give you an idea I’ve posted a couple more pics just showing the spread. But like i said as soon as i seated the projectile out the problem was solved.

W.R.Buchanan, the rifle is a Target rifle from yester year, it’s a single shot with a tight action and specs, it is a single feed so i don’t need to worry about mag issues but i take on board what you say about the protection that the neck of the case will give the base of the bullet. It makes a lot of sense. However I am a little sus on crimping as the neck tension alone is tight. i haven’t flared the case or like i did with some other test loads by running a 303 expanding ball through the mouth. This time i simply sized and seated.

Academic and Sav you are on the right direction to Yoda's identity :)

its poring with rain here at the moment but i will head out to the man cave and load up some for fun tonight. I also have a Fultons regulated .303 and a P14 that are next on the load development schedule, sadly the Fultons has been sporterised but is next on the restoration list.

but tonight at the range I am going to sort and batch a good group of projectiles, size them down gradually, weigh and inspect. These ones i will test next week to see the difference and will post the results, I will also try and get a chrono as it will be interesting to see what its doing.

Again thanks for comments

the pics below: 1 cm target shows 1 fouling and 2&3 being differing powder weights, 10 and 11 i think( dont have the range book with me) at 50 meters
however at 100 meters the results were less than desired at an inch target

[JeffinNZ]

The bullet is a CBE 313 215. .3135/.304 as cast.

Actually Tertle, those holes look a bit egg shaped. I wonder if your 1 - 12 twist is marginal for the 205gr bullet at that speed? Perhaps they have caught "wobbly bottom syndrome" from the Cruise Missile bullets in your loading room.

YODA! I am much prettier than YODA.

[Tertle]

I have come up with an ingenious plan to stop the wobbly bottom syndrome from spreading!

Think you will appreciate it

[W.R.Buchanan]

tertle: if this is a single shot target gun then, expanding the case to where you have about .001-.002 press on your sized bullet is the correct amount of neck tension. The Crimp is a separate function altogether and is done for two purposes. 1. to hold the bullet in place while in the magazine, not necessary for your application. and 2. to insure consistant burning of the charge.

My standard load for this bullet in my .30-06 is 25gr of 5744, with a solid crimp. It runs about 1850fps. That is in a 1-10 twist barrel. I get decent accuracy for use in shooting steel targets out to 200yds with iron sights. Like Jeff in NZ mentioned above you might not get that bullet stabilized with a 1-12 at lower speeds. They are kind of long, still Lyman 49 lists 20-27 gr of 5744 for the .308 with this Boolit with vels of 1600-2000fps, as having the best accuracy for this bullet. I don't know what the low end of the speed willl yeild for accuracy. Still you need the crimp for good consistant ignition.

Since you're trying different things it wouldn't hurt to add the crimp it is certainly one of the bigger varibles.

Randy

[Tertle]

Just got back from the range, late night!

Randy, I will give it a try,and get back to you with results. Not done a lot with crimping so will have a read and get my head around that. I understand the concept just the brain is telling me that there should be enough constant neck tension already, but like i know, sometimes its worth trying something a little left field.

I've just weighed brass and projectiles, getting rid of the ones that don't measure up and sticking with a good core of ingredients to make the next batch.

I am though going to look at borrowing a chrono as that will tell me if my loads are going in the right direction velocity wise.

however will be dropping the rifle in to be fitted with the suppressor in the next few days so it could be a week or so befor i can continue in the process, however it could be 303 time :)

[Artful]

This might be helpful for you to read
http://www.quarterbore.net/forums/showthread.php?t=280

You may find that trailboss is position sensitive in the case, so you might want to orient the powder the same before each shot.

[W.R.Buchanan]

Tertle: my bro and sister and law are docked in Aukland right now. They are Sailboat Cruisers, and bounce back and forth between NZ and Fiji, since you guys only allow foreigners to stay for 6 months. Too bad we don't do that here in the US.

The supressor will probably change everything, so don't be surprised.

The crimp needs to look like the top edge of the case is just rolled into the top groove of the bullet. You will seat the bullet normally and to where the case mouth is just at the top of the top groove, then you remove the seating stem completely or back it way out, and adjust the die down until it starts to roll the case mouth in. You will feel this in the lever stroke of the press. Keep adjusting the die down a llittle at a time until the crimp is about .030-.040 long when viewed from the outside of the case, and rolled smoothly into the crimp groove.. By then you will have a good hold on the bullet. I try to find another seating die to use as my crimp die so I don't have to mess with my seating die, something extra to prowl the gun shows for..

Unfortunately I can't take a close up enough picture of the crimp to really show this, You can kind of see it in the pic of mine above. Just remember creap up on it and look for a smooth roll about .030 long.

The whole purpose of the crimp is to allow the charge to build up pressure before the bullet starts traveling down the barrel.

Many powders require a certain amount of pressure to build up so they burn right. In other words they have specific pressures that they burn completely at.

That's why you can't reduce a charge of powder like H110 below the starting loads recommended. It doesn't burn correctly because it doesn't achieve it's correct burning pressure. The other reason with H110 is that if the case is loaded below half full and the powder is laying on the side of the case and below the flash hole the whole open space of the charge will burn at once and spike pressure dramatically as opposed to the charge burning from rear to front which takes longer. This is called flash over. It is not a good thing!!!

You might look at XMR 5744 powder as it lends itself well to reduced loads, and accuracy is usually good. It is usuable in alot of cartridges including .308 and .30-06, .303 and just about anything else you can think of. It has one really useful trait, it is not postion sensative, and burns consistantly no matter what position the case is in at firing and no matter how full the case is. Still needs a crimp.

The stuff is not cheap but it does work well.

Randy

[JeffinNZ]

XMR 5744 is not available in the Antipodes unfortunately.

[hornet fan]

Tertle,

I am watching this thread with a great deal of interest as I have been wanting to do the same thing for a while now, minus the suppressor.

Keep us posted on your results.

[Tertle]

Hey there Hornet, Thanks for the email.

I’ve been doing a little tinkering at the moment, with some real odd results; hence my lack of posting as it has me scratching my head instead.

The story goes like this....

I made up a batch of the usual and put it over a Chrono, first few had reasonably similar speeds, then things went to custard, not normal custard, but the real lumpy odd type!!!

Then the groupings were as erratic as a real erratic thing!

Now the odd thing is the only variation was a new batch of gas checks...... so i went back to the drawing board and this time made up a batch of three loads to test. Weighed brass, weighed lead, weighed and reweighed powder load, gently sized projectiles from their cast sizing to 312 to 310 to 309. I then went go through the brass sized, recheck flash holes and debured etc etc, i even tossed out any that when priming seemed to easy to seat the primer. Even annealed the brass.

result..grouping only slightly better but poor and erratic. However some grouped and then it went slightly spastic.

I went through the normal pre opp checks and observed a slight jump in the reticule when i dried fire but this was on about the third dry fire, slight but enough to concern me, but thinking was i seeing things to excuse my pathetic shooting so i had another guy look at the scope and he too saw the jump, but it seemed to return to where it was......well i thought it did.

So.. im in the midst of getting a new scope and retesting the loads..... and im trying to find some of the old gaschecks and again re test the loads.

But on the positive side, looking now around 9.5 with a wool filler, and have a batch of better brass and consistent components.

so i will have a shot on the weekend to and then its off for suppressing, i will update as i go, but the hope is to rescope and have a rifle that will group a little better and then i can go to the other spectrum and go for a fast hard hitting round.

Im now wondering what the actual problem was and when did it actually occur? Gas checks and a slightly off scope vs a hopeless shot? hmmmmm

[mpkunz]

Right on, man!! Those are good groups. I have been interested in a sub sonic load because buying Lapua sub rounds is getting expensive! You have given me some really helpful ideas. BTW: I like that boolit! Can you find out what it is? Maybe ask Yoda? I tried using the force, but it hasn't had coffee yet.


FWIW, to get the best results out of that long thin bullet as subsonic velocities, it will be better stabilized if fired backwards. Gonna look like a wadcutter when loaded but if you fire them nose first below Mach 1, Cp and Cg are reversed, and it will start to tumble the minute it leaves the barrel.

[JeffinNZ]

If he fires it backwards he will shoot himself..............

[Tertle]

But I would get a tighter grouping!!!

[JeffinNZ]

But I would get a tighter grouping!!!

If you shoot yourself you'll never know. Oh what a novice you truly are.

I still say the 1 in 12 twist is too slow for that bullet at that speed. Trying running with the rifle JUST before you pull the trigger. :!:

[Tertle]

scope now in shop, so i will do a load for sunday and hopefuly post a result, aiming of course in the right direction and being very very still![smilie=1:

[MaxJon]

scope now in shop, so i will do a load for sunday and hopefuly post a result, aiming of course in the right direction and being very very still![smilie=1:

Tertle, sounds like you are getting somewhere. I crimp my .308 subs and drill out the flashholes to 3.5mm, halved my group sizes! I use AP50N powder atm, (the next slowest below Trailboss) but am keen to try some Trailboss! I get way under an inch at 50m, (5 shots) have not yet tested at 100m. I really think crimping is way worth the effort! Worked for me!
Keep at it!
BB03

[Tertle]

unfortunatly had a small accident with 1 and half loverly bottles of bourbon with a very good friend who is a rather bad influence, who has also sadly shifted in 3 doors down from me........and shooting well was not on the cards after i woke up!

but this has not stopped me "researching"on the net.

Bullbarrel, do you use a filler? i am trying to work out what is best practice. Now i am ok with not using where there is enough powder to ensure a safe inginition, however when we are using small powder loads is it not best to ensure the powder is contained near the rear of the case. Dont get me wrong i am not saying jamed tight but i use a small wool wad keep things rearwards. just curious to others comments.

also drilling flash holes, again ive heard of it but not enough to really make form an opinoin, again comments.

but your another one advocating crimping, so something i will have a look into,cheers

[MaxJon]

unfortunatly had a small accident with 1 and half loverly bottles of bourbon with a very good friend who is a rather bad influence, who has also sadly shifted in 3 doors down from me........and shooting well was not on the cards after i woke up!

but this has not stopped me "researching"on the net.

Bullbarrel, do you use a filler? i am trying to work out what is best practice. Now i am ok with not using where there is enough powder to ensure a safe inginition, however when we are using small powder loads is it not best to ensure the powder is contained near the rear of the case. Dont get me wrong i am not saying jamed tight but i use a small wool wad keep things rearwards. just curious to others comments.

also drilling flash holes, again ive heard of it but not enough to really make form an opinoin, again comments.

but your another one advocating crimping, so something i will have a look into,cheers

Tertle, have you noticed a sooty deposit arond the case neck?? More than likely i would say? The low pressure of the uncrimped subsonic load does not expand the case to seal in your chamber. If you crimp em that should dissapear, due to the case sealing the projectile in the case, therefore a more consistent and better burn. When uncrimped it seems as though the powder charge is burnt before the projectile gets going. Dont quote me on that tho. Drilling the f/holes just gets a better ignition/flame to the small powder charge. Get yourself a crimp die, the Lee one works fine. No fillers used! If you google = subsonic .308 load data. You should find all info you need, it is the first one, Develop Subsonic.
(members.shaw.ca/........)
No shooting for me today either, had a beer induced head ache! lol
Keep at it mate!! Hope all is getting back to normal over your way.
BB03