Slugged my .308 barrel and it came out at .306??

[SKSer]

Hi guys, I have been a Lurker for awhile now ever since I started looking into casting. Im a regular over at Calguns, which is how I found out about this forum. My first cast loads were for a 7.62x39 load for and SKS and an AK, and I found a ton of info on this site that helped me load a successfull load, I am very greatfull for that :).

Ok so here is my question I have a stevens 200 in .308 and i just slugged it. It came out at .306 in the grooves and .303 at the lands. At first I thought it was my calipers but so then I measured a .224 bullet and it checked out at .224.

Is it normal for a .308 Barrel to be this tight? It is a new rifle. It maybe has 150 rounds down the tube. If this is the case, what should I size the bullets to?

I tried loading the cast bullet that I was using for the SKS/AK load for it which is the c312-155-2R
http://www.midwayusa.com/viewProduct/?productNumber=752956
sized down to .309 and it did horrible as far as accuracy, I couldnt even hit a 18x18" paper at 100 yards. I dont know if I was putting to much powder behind it (4 different loads 25-26-27-28 grns of h4895), or if it was too light of a bullet, or maybe now knowing about the sizing difference.

I guess Im just trying to start from scratch with this rifle, here is the info I got so far.
bolt action Stevens 200 in .308
slugged to .306 grooves, .303 lands
22" barrel
twist rate rate is 1 in 10

I was thinking of trying a heavier CB, something like this c309-200-1R
http://www.midwayusa.com/viewProduct/?productNumber=183267

what do you guys think?

Thanks for taking the time to read this confusing thread, It turned from a thread about my slugging results to all of this :mrgreen:

[mooman76]

I would say it's not normal, and not totally unheard of, but it is not a problem either, in fact it could be to your advantage because you can use a bigger selection of boolits. I would slug again to be sure and does your gun have a odd number of grooves? That could be it.

[outdoorfan]

It seems that you're measurements might not be quite right. But, I'm not saying that they aren't. If they are spot on, then you only have .0015 tall rifling...no good. Gonna be hard to grip the boolit. Bullets would probably work better.

However, if it's a new barrel, then the grooves need some wear to open up. I think (not absolutely sure) that they could open another .001 or more with some "break-in" time. It was once suggested to me by a senior member here that a stainless steel bore brush could be used to facilitate that and speed things up. (SS brush instead of a regular brass brush when doing the normal routine cleaning.)

On the other hand, I've heard it said that it's hard to get an accurate reading on the groove diameter unless the soft lead slug is pounded pretty good to fill the bore. In other words, it needs to be blocked on the bolt side while you pound on the muzzle side with a big sledge. Heavy hits with a big hammer rather than light raps with a small one is the key (make sure you don't ding the crown or the bore). When you feel that the slug has filled the bore all it can, then tap it out. Make sure you use some good lubricant in the bore before doing this. That procedure might get you another .0005 or more.

I had a 30-06 that was .303 bore and .308 groove. Never shot quite good enough, but I could never prove that it was the main cause of inaccuracy.

BTW, what did the throat diameter measure? Idealy, you want to size the boolit to fit the throat.

Anyway, someone else can answer the load questions.

[Doc Highwall]

You should be using a set of micrometers to measure that dimension, not calipers. Get yourself a cheap pair of 0-1" that will measure to .0001" from Harbor freight and you will not regret it.

[SKSer]

I would say it's not normal, and not totally unheard of, but it is not a problem either, in fact it could be to your advantage because you can use a bigger selection of boolits. I would slug again to be sure and does your gun have a odd number of grooves? That could be it.

it has 6 grooves, I could deffinately slug again to double check.

[SKSer]

It seems that you're measurements might not be quite right. But, I'm not saying that they aren't. If they are spot on, then you only have .0015 tall rifling...no good. Gonna be hard to grip the boolit. Bullets would probably work better.

However, if it's a new barrel, then the grooves need some wear to open up. I think (not absolutely sure) that they could open another .001 or more with some "break-in" time. It was once suggested to me by a senior member here that a stainless steel bore brush could be used to facilitate that and speed things up. (SS brush instead of a regular brass brush when doing the normal routine cleaning.)

On the other hand, I've heard it said that it's hard to get an accurate reading on the groove diameter unless the soft lead slug is pounded pretty good to fill the bore. In other words, it needs to be blocked on the bolt side while you pound on the muzzle side with a big sledge. Heavy hits with a big hammer rather than light raps with a small one is the key (make sure you don't ding the crown or the bore). When you feel that the slug has filled the bore all it can, then tap it out. Make sure you use some good lubricant in the bore before doing this. That procedure might get you another .0005 or more.

I had a 30-06 that was .303 bore and .308 groove. Never shot quite good enough, but I could never prove that it was the main cause of inaccuracy.

BTW, what did the throat diameter measure? Idealy, you want to size the boolit to fit the throat.

Anyway, someone else can answer the load questions.

I used gun oil to lube the bore and then I used grease for the slug.

I re-measured the slug and had the same results .306 groove and .303 at the lands. On this barrel the grooves are really wide and the lands are really thin.

I would say that it did fill the bore pretty good, I flattened out the slug initially and it had a diameter of .320 before I pounded it through, it even shaved off a little lead ring at muzzle.

how would I measure just the throat? I would think i either need to chamber cast because you would think that if I just closed the bolt and hammered on the slug it would just fall into the chamber.

I do have a little info about the chamber...

I just measured a cast loaded round at the case neck and it came out at .338, I then measured a factory load at the case neck and it also came back the same at .338

then I measured the cast bullet just above the case neck and it came back at .309
then I measured the factory bullet just above the case neck and it came out at .304

with the cast loaded rounds, they are some what hard to chamber vs the factor loaded rounds, Im assuming because the difference in the bullet size just above the case neck, being Im pushing a .309 bullet into the .306/.303 throat, assuming that is what it is. the factory load chambers with ease seeing how it measured .304 just above the case neck.

[SKSer]

You should be using a set of micrometers to measure that dimension, not calipers. Get yourself a cheap pair of 0-1" that will measure to .0001" from Harbor freight and you will not regret it.

Thanks for the advice, maybe I will pick up a pair this week at HF

[outdoorfan]

I doubt the throat is less than .309, and probably more. To pound a soft lead slug into the throat to get those dimensions you need to fill an empty case with lead up to the case mouth. Then insert that into the chamber and close the bolt. There's your backstop to pound against.

[SKSer]

OK I slugged a second time, this time I went from the breach and went in just into the throat, then backed out, and I had the same results .306 groove, .303 land.

I started out with a .318 size slug and had a little lead ring left over again.

[Ben]

I've read this several times, something about this doesn't add up. .306 / .303

The height of the lands with those numbers are way out of spec. for the typical .30 cal barrel. Something isn't right ?

[SKSer]

I know I was shocked when I took the measurements too. It fires jacketed rounds great. I get MOA to sub MOA with factory loads. I havnt even tried a jacketed handload yet, I was looking at buying some jacketed bullets, then i was thinking "he** I can get a Lee mold for it for the same price as 100 jacketed rounds" which leads me to here.

Im firing up the ol bottom pour right now to fill a case up with lead to try outdoorfan's method and see if I get any results. If this turns out the same, Im going to call savage tommorow to se if this is the norm for their barrels.

[Blammer]

ok, I'd forget the slugging dia for a bit and I would try a .309 dia boolit with the velocity about 1800fps with whatever powder will get you there with that wt boolit.

Make sure you have flaired the case mouth before seating the boolit to keep the boolit from getting deformed or shaved when seated. Also don't "crimp" the cartridge into the boolit.

Give that a go first and see what you get.

One more thing, clean the barrel really really well first before shooting the cast, try to get as much copper out of the brl as possible. I'd then take a patch soaked with the boolit lube you're useing and run it down the brl to give it a "slight" coat, to help with those first few shots for accuracy wise.

let us know how that goes.

[outdoorfan]

Im firing up the ol bottom pour right now to fill a case up with lead to try outdoorfan's method and see if I get any results.

Getting your throat dimensions is never a bad idea. Then you'll know just what you need to do to fit the boolit properly, or at least you'll have a baseline with which to then experiement with.

[SKSer]

Ok here is the update, using outdoorfans method of the lead filled case, and after several broken oak dowl rods and a bent brass cleaning rod :lol: throat dimensions are .309 groove and .303 land. Does that sound more normal as far as the land compared to groove?

Thanks again for all the help guys.

[Blammer]

yes that sounds more "normal"

I'd try for a boolit at .310 dia and go from there.

[SKSer]

Ok cool, I will be picking up a .310 sizing kit with my next purchase

on another note, as I mentioned earlier I tried the CB from this mold initially: c312-155-2R
http://www.midwayusa.com/viewProduct...tNumber=752956
should I try to dial this in? I mean its designed specifically for the 7.62x39. Or should start fresh with a longer and heavier CB designed more for the .308. Im not trying to break any records or make miracles happen, I would prefer an easier CB to dial in, Im just wondering if a heavier longer bullet would be easier to dial in.

also, when I was chambering these last loaded rounds, Im pretty sure I was pushing the bullet into the lands as it was fairly hard to chamber, so I need to adjust my seating depth.
My question is, do I need to worry about how far down the base of the bullet hangs in the case? I was thinking I needed to keep the base of the bullet above where the shoulder and neck meet or does it even matter.

[Ben]

SKSer

Continue seating the bullet until you feel " slight " resistance when you close the bolt....not hard resistance.

If the g/c hangs down below the case neck, don't worry about that. " Old Tales " suggest that is a " no-no" , but I've never been able to determine any truth to that.

By the way, what are you using to put a slight " bell" or flare on the mouth of the case prior to seating the bullet. About 3/4 of the gas check should enter the case mouth freely. If you don't have that amount of flare on the case, you need it.

Ben

[SKSer]

I have just been using this with my case prep http://www.midwayusa.com/viewProduct/?productNumber=389104 it came with my lee kit, it doesnt really bell the case, it just shaves off the inner burr and gives it a 45 degree or so taper. should I put something else on the shopping list?

[outdoorfan]

Good job on the throat slugging. Now, I'm a little confused when you say the throat is a .309 groove. Are you saying that the throat's maximum diameter is .309? If that's the case, then you're not going to fit a .310 boolit in there. Usually the throat is .310 or bigger at it's widest point, but then it tapers down into the "normal" groove diameter of .308 or so (in your case maybe .309).

Get the Lyman M die for belling the case mouth. Works great!

Edit: I keep thinking you're shooting the 30-06, which you're not. Maybe the .308 Winchester throat dimensions are tighter.

[gerrycan]

SKSER
Lee make a case flaring tool to bell the case mouth so as not to shave down the projectile.You can adjust it for most cals., Gerry

[Blammer]

until you get the lyman M die, use a pair of long needle nose pliers to push in and spin around a bit to get some flair on the case mouth. Won't take much.


and yes the boolit you have should be no real problem to start with. IF the nose is .301 or so in dia that will be a boost for you, if it's smaller, you may have difficulty.

for starters, i'd look at trying to get a 311041 Lyman.

[Ben]

SKSer :

I think a big portion of your accuracy woes may have to do with the fact that you're trying to seat a cast bullet into the neck of a case that has no flare on it.
Example....you're trying to put a .309 bullet base into a .306 hole in the case neck. Won't work....you've got to get a flare on the end of the case to prevent damage to the fragile cast bullet.

Using a deburring tool is fine during your case prep, but it is no substitute for an adequate flare to get the g/c'd bullet an easy start into the case neck. Buy this die for $11.49 and you'll be good to go.

http://www.midwayusa.com/viewProduct/?productNumber=140461

Remember , If 3/4 of the gas check won't go into the flared case you don't have enough flare .

I don't like the Lee Die as well as I like the Lyman M die, but the Lee ( as usual ) is priced less than the Lyman M die. If you can afford the extra money I'd go with the Lyman M die, if $ is a concern, the Lee Expander die will get you started down a better path.

If you don't buy either one, get yourself a tapered punch, a couple of soft taps and you'll get a soft flare on the end of the case neck. Use the rule of getting 3/4 of the g/c into the case with whatever method you end up choosing.

I'll bet this make about an 800 % increase in your accuracy. You were mangling the cast bullet with your seating technique of using no flare.

See if these photos help if you choose to go in the direction of the tapered punch until you can obtain a case neck flare die. I used this system for MANY years to shoot some pretty impressive cast bullet groups until I was able to obtain a Lyman M die :

http://img.photobucket.com/albums/v494/haysb/Case%20neck%20expanding/Edited1.jpg

http://img.photobucket.com/albums/v494/haysb/Case%20neck%20expanding/Edited2.jpg

http://img.photobucket.com/albums/v494/haysb/Case%20neck%20expanding/Edited3.jpg

http://img.photobucket.com/albums/v494/haysb/Case%20neck%20expanding/Edited4.jpg

[SKSer]

SKSer :

I think a big portion of your accuracy woes may have to do with the fact that you're trying to seat a cast bullet into the neck of a case that has no flare on it.
Example....you're trying to put a .309 bullet base into a .306 hole in the case neck. Won't work....you've got to get a flare on the end of the case to prevent damage to the fragile cast bullet.

Using a deburring tool is fine during your case prep, but it is no substitute for an adequate flare to get the g/c'd bullet an easy start into the case neck. Buy this die for $11.49 and you'll be good to go.

http://www.midwayusa.com/viewProduct/?productNumber=140461

Remember , If 3/4 of the gas check won't go into the flared case you don't have enough flare .

I don't like the Lee Die as well as I like the Lyman M die, but the Lee ( as usual ) is priced less than the Lyman M die. If you can afford the extra money I'd go with the Lyman M die, if $ is a concern, the Lee Expander die will get you started down a better path.

If you don't buy either one, get yourself a tapered punch, a couple of soft taps and you'll get a soft flare on the end of the case neck. Use the rule of getting 3/4 of the g/c into the case with whatever method you end up choosing.

I'll bet this make about an 800 % increase in your accuracy. You were mangling the cast bullet with your seating technique of using no flare.

See if these photos help if you choose to go in the direction of the tapered punch until you can obtain a case neck flare die. I used this system for MANY years to shoot some pretty impressive cast bullet groups until I was able to obtain a Lyman M die :

http://img.photobucket.com/albums/v494/haysb/Case%20neck%20expanding/Edited1.jpg

http://img.photobucket.com/albums/v494/haysb/Case%20neck%20expanding/Edited2.jpg

http://img.photobucket.com/albums/v494/haysb/Case%20neck%20expanding/Edited3.jpg

http://img.photobucket.com/albums/v494/haysb/Case%20neck%20expanding/Edited4.jpg

thanks alot Ben, i was wondering if i could do it with a modified punch. It makes alot of sense. I was thinking about it like a jacketed bullet were the case would pretty much wrap around the bullet. I didnt really consider the lead bullet being much softer then the brass case which is what would cause the bullet to get mangled up.

One question on this, do I leave the flare as is after I load, or is there something else I should do?

I also wanted to thank everyone very much for helping me out with all this info, I have learned a ton of info in this thread alone.

I will keep you guys updated on my results, it may be a bit, as I have a bunch of reloading to do before i take my next range trip, I just drained my stock pile a couple of weeks ago. :Fire:

thanks again.

[Buckshot]

.............My one year old Savage M110FP in 308 slugs .300" x .307", with a .309" throat so it's a tight barrel. The NEW barrel, that is. When I bought the rifle and got it home and began cleaning it the barrel felt rough. I don't have a borescope but checking from the muzzle with a very bright light the lands WERE very rough. This was disturbing to me and I felt it was totally out of place. My Savage M112 Varmint rifle in 223 has a barrel as slick and shiny smooth as chrome.

I never contacted Savage. I boxed it back up, included my reason for returning it and suggested a look see by management into the QC dept. In about 2 weeks I got the rifle back with a new barrel and the following factory target:

http://www.fototime.com/B30B1DA91688D67/standard.jpg

On their supplied data sheet the target was shot with Federal 168gr Match. Three rounds @ 100 yards.

................Buckshot

[Ben]

SKSer :

You are very welcome for any help that you may have received from my post.
I'm glad you feel like you're learning. In " this game ", you'll never stop learning. I'm 61 and started casting when I was 16 yrs. old. As I read on this forum, I continually learn useful things that make my casting and shooting go smoother.

As to the flare that is still left on the case neck, I don't remove mine. It is so minor that it has absolutely nothing to do with chambering. I've left it on the loaded rounds when chambering in single shot and bolt action rifles without a problem. If I were loading the rounds for a lever action, I'd probably remove the crimp and try to crimp into the bullet.

As you can see, not removing the crimp doesn't seem to have any adverse effects on accuracy for me :

http://img.photobucket.com/albums/v494/haysb/311290%20Hollow%20Pointed/PICT0009b.jpg

[SKSer]

Ok cool, Thanks again, VERY nice group BTW.

[SKSer]

Good job on the throat slugging. Now, I'm a little confused when you say the throat is a .309 groove. Are you saying that the throat's maximum diameter is .309? If that's the case, then you're not going to fit a .310 boolit in there. Usually the throat is .310 or bigger at it's widest point, but then it tapers down into the "normal" groove diameter of .308 or so (in your case maybe .309).

Get the Lyman M die for belling the case mouth. Works great!

Edit: I keep thinking you're shooting the 30-06, which you're not. Maybe the .308 Winchester throat dimensions are tighter.

I re-measured this morning and it seems to be .309 right down to the start of the chamber. The rifling looks like it starts just a tiny bit above the end of the chamber maybe 1/32 or so.

[outdoorfan]

Okay, now that you have the dimensions you can pick a bullet design that will fit well, & off you go to some fine accuracy. :p

[SKSer]

OK here is an update, this slugging thing was bugging me all week, I didnt feel like I did it 100% so I wanted to try it one last time, but I had to wait to get some more time. I also was thinking of a way to slug in the middle of the barrel as well, so here is what I did. I cut up my old brass cleaning rod to use in the process. I flattened out the top of the lead filled case so because there was a dome left from when I poured, so that way I would get a nice flat bottom on the slug. So then I sent a slug down to the case, then I put in about a 10 inch brass rod then another slug that would "spread" more in the middle of the barrel then I put in another rod to hammer to spread both of them out. (man I hated hammering on the gun like this, but i figured the thing is designed to contain an explosion from a .308 round, and I wasnt really hammering, I was just giving a lot of "good solid taps").

so here is the end result:

at the base of the throat, just after the top of the case neck I get a measurement of .0310

just above that, about 1/32, the rifling starts and it tapers down to .309groove/.303 land

now as for the slug in the middle of the barrel, I get .308 groove /.303 land

so with this knowledge now, what should I size the bullet to? Should I still start with a .310 bullet as suggested earlier? Thanks Guys.

outdoorfan you were right:

Now, I'm a little confused when you say the throat is a .309 groove. Are you saying that the throat's maximum diameter is .309? If that's the case, then you're not going to fit a .310 boolit in there. Usually the throat is .310 or bigger at it's widest point, but then it tapers down into the "normal" groove diameter of .308 or so (in your case maybe .309).


ETA: good call guys on the no case belling issue. I just pulled apart an unfired cast round and measured the bullet and it came back at .3075 even though I sized it to .3095 , so not belling the case shaved off .002 off the CB which im sure is detrimental seeing how the tightest part of the bore is .308 which is still .0005 looser then the shaved bullet.

[Doc Highwall]

I have been sizing my bullets .310" and getting great accuracy. I am going to test it later with .3105" and .311" because until I try, I will not know what the gun likes the best with out hard data. I also have other guns with slightly larger groove diameters so this puts me closer to what I should need for them on sized diameters.

[SKSer]

I have been sizing my bullets .310" and getting great accuracy. I am going to test it later with .3105" and .311" because until I try, I will not know what the gun likes the best with out hard data. I also have other guns with slightly larger groove diameters so this puts me closer to what I should need for them on sized diameters.

Are your bore measurements similar to mine? I have a lee .309 sizer that sizes at .3095, I might try to open it up a smidgen to .310 with the sandpaper, steel rod method. I didnt even see a lee sizer for .310 on midway, they have .308, .309 then it jumps to .311, which i have also for the 7.62x39.

[outdoorfan]

Are your bore measurements similar to mine? I have a lee .309 sizer that sizes at .3095, I might try to open it up a smidgen to .310 with the sandpaper, steel rod method. I didnt even see a lee sizer for .310 on midway, they have .308, .309 then it jumps to .311, which i have also for the 7.62x39.


What I usually end up doing is trying slightly bigger and bigger sizes until they won't chamber anymore. That means you might need another sizer after you possibly bugger up your .309 by honing it out too miuch. OTOH, if your boolits are sizing to .3095, and you just measured your throat at .310 at its widest point, then you might want to leave it as-is. Another option is to just barely tickle that .309 sizer open a tad more until your chambered round drags ever so lightly, if it isn't already.

[SKSer]

Hey Guys, I wanted to let you guys know how it finally ended up.

So I finally made it out to the range yesterday, and I loaded this round the same as before with the addition of the flaring of the case mouth, and that ended up being the cure.

It shot very consistently. I have my scope set for regular full load FMJ data, and this CB load was printing about 10" low at 100 yards, which seems to be about normal as its a reduced load, it felt like it had about 50% recoil compared to the factory load. Like I said before, it was very consistent though. the windage was dead on and I even had a point of aim with my scope (right at top of the third step down from the middle of my cross hairs)

I tried 2 different loads, both had Identical results

Mold was a lee C312-155-2R made for 7.62x39, clip on WW alloy sized to .309

load #1 (original load) h4895 25 gr, CCI BR primers, OAL 2.665

load #2 "The Load" by C.E. Harris, Red Dot 13gr, CCI BR primers, OAL 2.665


I wanted to say thanks to everyone at CB for your guys help, you guys were awesome.

[mroliver77]

That boolit shoots in every .30 I have tried it in! You might try sizing to .311 to see if it makes a difference. As long as it chambers easily .311 should work fine. I have many .30 cal and .311 is not TOO big for any of them safety wise. You did not give any particulars of group size etc. Keep up the good work!
Jay

[CWME]

Good to know that this boolit shoots good in all 30s. I just found a 2 cav gently used yesterday for $15. Cast a nice looking boolit too. Excited to try it out.

[SKSer]

That boolit shoots in every .30 I have tried it in! You might try sizing to .311 to see if it makes a difference. As long as it chambers easily .311 should work fine. I have many .30 cal and .311 is not TOO big for any of them safety wise. You did not give any particulars of group size etc. Keep up the good work!
Jay

Thanks.

I was getting 2-3 inch groups at about 80 yards, I only shot a few 3 shot groups at paper. Everything else was just targets, 2-liter bottles filled with water and steel plates between about 80-160 yards. I was hitting an 8" by 12" steel plate at about 160 yards every time.

I have a .311 sizing die, so I could definately give it a shot.

[SKSer]

Good to know that this boolit shoots good in all 30s. I just found a 2 cav gently used yesterday for $15. Cast a nice looking boolit too. Excited to try it out.

It shoots great in 7.62 x39, which is what it was designed for, I get better accuracy then some factory loaded ammo

[PatMarlin]

Late note but I've used the LEE flare kit die set for all of my calibers since it came out, and it works very well, easy to set up and put the flare on you need.

[10x]

See how well cast bullets shoot out of the gun. You can resize cast bullets to match the bore if need be.
Watch your pressure signs with any loads approaching maximum.