Some times we need to re-think our data.

[Sailman]

A couple of months ago I had a bran new Remington 1944 barrel put on my 30-06 Springfield target rifle. About 50 years ago I took the first 30-06 Springfield I ever owned and put it in a target type stock, glass bedded the action, installed a commercial trigger, and mounted Lyman sights to the action and barrel. This was my target rifle and I shot many a match with this rifle. Since I had some bran new GI barrels, I decided to have a new GI barrel installed and have a scope mounted to the rifle. Since I don't use this rifle in matches anymore, it was going to be my test-bed military rifle ( with the scope you eliminate apx. 95 percent of the sight error but you still have the wobble from the heart beat ).

With the new barrel I had to establish what dia. bullet it would shoot. I have never slugged any of my rifle barrels. Having sizing dies .308, .309, .310, .311, .312, .313, .314, and .315 for my Lyman Lubicator / sizer, I would test what bullet dia. the barrel would like. My test would be just to start loading ammo with .308, .309 etc. sized bullets to see which shot the best.
My first test indicated that a .308 dia. bullet was required. However, my tests required that after I establishe what powder and powder ammount shot the best, I would go back and test again for bullet dia.

I had been working with bullet # 308-165-SIL. The load that worked the best for me was 14gr of 4227.

For my second round of bullet diameter testing I decided to test as follows:

1. 13 gr. of 4227-----308-165-sIL -----10 rounds .308 dia. and 10 rounds .309 dia.
2. 14 gr.----------------------------------------etc-------------------------------------------------
3. 15 gr. --------------------------------------- etc------------------------------------------------
4. 16 gr.----------------------------------------etc.------------------------------------------------

Results-----------------------------------------------------------------------------------------------

With every catagory of powder charge, the .309 dia. bullet shot best. The following are group sizes got from this test. The testing was done at 100 YD:

13 gr.-----------.308==3 7/8-----------------.309==2 7/8-------------------------------------
14 gr.-----------.308==3 1/2-----------------.309==2 1/16-----------------------------------
15 gr.-----------.308==3 1/4-----------------.309==2 1/8-------------------------------------
16 gr------------.308==4 1/4-----------------.309==3 1/8-------------------------------------

Remember, in this test a scope was used so old eyes are not a factor.

I have always considered HEAT as factor in testing for bullet size. Steel does expand with heat ( think of what happens to rail road rails ). By establishing the size of bullets by shoot---testing, I believe that although sulgging a barrel certainly helps to get some idea as to what dia. the bullet should be sized, the final answer is established by shoot---testing.

Just my opinion.

Sailman

[grumpy one]

I'm trying to relate your experience with mine. I too started off without slugging, to see what bullet diameter worked. With a 30-30 microgroove I began shooting bullets sized 0.310, and achieved fairly poor results. However when I slugged the barrel I got 0.309, so I "knew" my problem wasn't bullet diameter. Of course it was bullet diameter, but slugging a leaded barrel always seems to give me a result about .001 smaller than the bullets I'd been using had been sized to. Measured at the breech and muzzle, the barrel was 0.311. I tried sizing to 0.312, and within two or three shots the results suddenly were excellent.

With a deep-rifled 30-06, I made much the same mistake at much the same time. I shot 0.310 bullets, and got fairly poor results (initially 2 inch groups at 55 yards) that slowly got worse (eventually 3 inch groups). As one of many semi-random experiments I shot one group with the same bullet sized 0.311. The group was even worse than usual (3.4") and I took this to mean the bigger bullet hadn't helped. However when I reverted to 0.310 sizing, the next two groups I shot were both 1.1" - vastly better than I'd ever seen before with a cast bullet. I immediately formed a theory that the five 0.311 sized bullets had blown lead out of my barrel, and left it fit to shoot. I therefore switched to sizing all my 30-06 bullets to 0.311, and sure enough, when I shot the old 2 - 3" group loads again, some of them miraculously became 0.6" group loads.

The point of this long meandering history is that I think you shouldn't fire just one group with a different bullet size, and feel confident that you'll immediately get a valid result. The barrel may be initially snotted up with lead, and it won't shoot until you blow it out one way or another. Measuring the size group you shoot while barrel-cleaning won't necessarily tell you much.

Geoff

[swheeler]

That's why I take "range reports" with a grain of salt. When I read that someone has found the sweet spot, after one or two groups I get a chuckle. When I say proven load, that means a MINIMUM of 25 ten shot groups to arrive at accuracy standard for that load in that rifle, hum must be why I can shoot a barrel out, but never achieve that " every shot goes thru the same hole!"

[Sailman]

SWHEELER I am in total aggrement with you concerning the number of groups which should be shot before you can say this is what this load can do. It is basic statistics that says the greater your sample size the more accurate you prediction of the end result will be.

For this reason I like to shoot 20 shot groups. It is uncanny how many times the first 5 shots of a 20 shot group will print a very nice group, however, after 15 more rounds the group expans significantly. I have a lot more confidence in saying that this is what this load will do when considering a 20 shot group as opposed to a 5 shot group. I have even more confidence when I try a second or third 20 shot group especially if the 20 shots groups are shot on different days.

Sailman

[45 2.1]

3 shot, 5 shot, 10 shot, 20 shot, 50 shot groups? What are you trying to accomplish, see what the load does, what the gun does, what your ability to hold and manage your gun over a large range of barrel conditions? Fact is cold groups for hunting and normal benchrest groups differ greatly. Most barrels will walk on the 6th round and after unless you know how to handle the barrels condition. I would rather see what a large number of 5 shot groups do for normal shooting, 3 shot from a cold barrel for hunting does fine to. Ultimate accuracy would involve a machine rest without stock influences. This isn't a skeet match, is it.

[JDL]

A feller once told me how he tested his hunting rifles. He would run a dry patch down the cleaned barrel to collect any solvent or oil and take one shot. This was repeated daily for 20 days after which he had a 20 shot group to judge what the first shot would do from different conditions.
I guess this could be expanded to cover whatever was felt confortable. -JDL

[Buckshot]

............Neat test. Are you gonna try .310" or is the throat too small? I have an 03A1 Springfield and a .310" slug gets all scraped up.

Just for fun one time (so take it for what it's worth) I tried some slugs sized to .264" vs my normal .266" in a M38 Swede. No real reason to do it as accuracy I was already getting from this full military rifle was fine.

I fired 10 rounds of each at 100 yards. Each 10 rounds from an ambient temp barrel and each ten rounds were fired as: load, sight, fire, eject, load, sight, fire, eject, etc. The barrel was well warmed up after each 10 rounds.

The 10 rounds with the smaller sized slugs grouped demonstratively better then the .266" ones did.

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

[StarMetal]

I've written this before. Let's first just discuss huntin accuracy. I think Ross Seyfred described it best. Take you hunting rifle and load and go out to the bench, shoot one shot, go home. Repeat this the next day. Do so until you get the number of shots you want the group to be. If necessary clean the rifle and repeat the whole process to see if the results are uniform. Like he said the first shot from a hunting rifle is from a cold barrel. He also mentioned a fouled bore too. I would imagine you could do the test the same way except clean the barrel each day so you have a fresh slightly oiled bore if you want to see how it shoots that way if you don't believe in the fouled bore story.

Buckshot I'm surprised at you on that sizing. If you read the Lyman Cast bullet book you will notice that an awful lot of there suggested sizings are exact groove diameter. For years I shot all the 7x57 Mauser cast loads with my bullets sized at .284 as was the groove diameter of my rifles with excellent accuracy.

The only way to see what your rifle really likes is to try all the different things you can with the load, including different bullet diameters.

Joe

[Sailman]

Hunters and target shooters live in a different world. For a hunter, the most critical shot is the first shot from a clean cold barrel. For a target shooter, you usually have to shoot ten shots in ten minutes. It has been years since I shot in a military match but if I remember correctly you even have to shoot 10 shots in one minute for a rapid fire match.

For our military bolt action matches, we have to shoot 10 shots in 10 minutes. Before we shoot for record, most shooters will shoot 3 or 4 warmer shots to warm up the barrel. Does it not make more sence when testing loads for ten shot matches to test from a warm barrel and base you loads on conditions encountered in a 10 shot match shot in 10 minutes. Consequently, when developing loads for a 10 shot match, it makes good sence to shoot a 20 shot group.

Sailman

[Sailman]

Buckshot

Yes, I am going to test again using .309 and .310 sized bullets. By testing with .309 and .310 sized bullets I can verify the results with .309 and see if .310 can improve my groups.

As I have said before, I have never slugged a barrel. By testing using different sized bullets, I THINK, ----HOPE, that the results are the SUM of ALL the vairables
one can encounter.

Sailman

[Sailman]

Buckshot

I found your experience with the 6.5 Swede very interesting. I have one but never shot it so my knowledge about the gun / cartridge is very limited.

I was checking my Lyman manual for information about the 6.5 Swede . It states that the groove Dia. is .264. Lyman recommends cast bullets to be sized to
.266. From what you said, you were sizing the bullet correctly per Lyman's recommendations. In addition, you were satisfied with your results.

What interests me is did you slug the barrel? If so, what did it measure?

It is obvious what I am leading up to. If you did slug the barrel and it measured to the avertised size but undersize bullets shot better, then we have a very interesting situation. If however you did not slug the barrel than you may be the victim of a typical military rifle which have wide tolerances. If you did not slug the barrel and you got better results with the undersize bullet, it would seem that testing your rifle / load by using progressively larger bullets would be the way to go.

In addition, I like how you tested your loads. If you are not using this rifle / load for hunting, than shooting 10 round groops makes a lot of sence.

Sailman

[felix]

Be careful of lube buildup in the throat area. 20 minutes after the last shot in a group seems to be about max in my BR gun before the next group. Run a dry brush down there after each group if letting the gun sit (to cool off in the swede's case). ... felix

[Bucks Owin]

FWIW, H. Guy Loverin advocated bullet diameters of around .003" larger than bore diameter and he was interested in 500 yd accuracy.....

Dennis

PS Felix, haven't forgot about his article, just haven't got a "round tuit"...:roll:

[Buckshot]

.............Sailman, no I never slugged that rifle. I haven't really slugged more then the throat in quite a few years. I just used the .266" sizer as all my Swedes would pass a slug sized to that with no problem. It was the largest 6.5mm sizer available too.

I don't remember how I got the .264" die as I for sure didn't spend any money for it :-). The next question would be, did I try .264" slugs in my OTHER Swedes? The answer to that is no. They ALL shoot really well with slugs sized .266" so paying homage to the KISS principle I continue to size them to .266". The other evidence to the contrary notwithstanding!

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

[Char-Gar]

Sailman... I hate to be the fellow that rains on another fellow's parade, but none of those groups are worth bragging about.


Repeat those tests with .310 and .311 bullets and I would bet you would see the groups shrink even more.

I think most of us learned that bullets need to be sized to fit the throat and the barrel groove diameter is irrelevant. However you don't want to shoot bullets smaller than groove diameter. It can be done, but there are some special considerations to make it work.

I have five rifles in 30-06 caliber and only one won't accept bullets of .310 or larger. That one rifle is a 1954 vintage Model 70 Winchester and .309 is the max limits. I have two 03A3 rifles and both of them do best with .311.

The RCBS 165 SIL is a great bullet and a 03A3 barrel should be able to put 10 of them into 1.5 MOA or less with ease. Of course everything else must be right with the rifle,load and shooter load to do that.

I appreciate your data, but an examination tells me, thus far you have shown your rifle to deliver a better level of mediocre accuracy with .309 bullets vis-a-vi .308 diamter bullets.

Keep going to larger bullets and watch those groups shrink.

Also you need to know that by 1944 wartimes specs had increased on those barrels and .308 bullets may be less than groove diamter.

[Char-Gar]

Grumpy... Shooting leaded barrels is an excercise if frustration and nothing is to be gain in the way of knowledge by doing so.

A proper cast bullet load won't lead the barrel in any degree. If one does, then don't shoot it..period. Stop shooting, clean the barrel and try and figure out what went wrong that caused the barrel to lead.

I would guess your Marlin MG disappointment has very little if anything to do with the sizing diamter of the bullet. These MG barrel also run large in the land diamter and it is difficult to find bullets with noses large enough to work truly well. I have two 30-30 MG barrels and one runs .303 accross the land and the other runs a full. 305 accross the lands.

The SAECO .303 Brit bullet does well in the .303 land diamter, but it took a custom mold from Mountain Molds to being the big .305 into line.

I size the bullets .311 because the throats won't take anything larger.

[grumpy one]

Charger, when I leaded the MG barrel I was shooting straight foundry type. After leading the barrel I wore out 8 new bronze brushes (no, I was not reversing direction with the brushes in the bore) and used up two complete lead removal cloths cutting them into patches, after which the leading was barely reduced. I tried using strips of copper scouring pad wound around an old brush, doing that repeatedly until the strips of copper failed from fatigue, then winding on new strips and doing it again, until I'd completely used up one of those giant copper scouring pads. That had taken hours a day over a couple of weeks. I'd put quite a few hours trying to remove the same alloy in the same way from my 30-06 barrel, too, using up another half a dozen bronze brushes. I concluded that I wasn't going to get that extremely hard lead alloy out by mechanical scratching, all I was going to do was wear out the barrels from cleaning rod wear. So I tried shooting the right sized bullets with old Lyman (brass) gas checks with target loads (15 grains of 4227 in the 30-30 MG, and 20 grains of 4227 in the 30-06 FN). Both rifles recovered within five shots and began shooting accurately with water-dropped bullets of 3% tin, 5% antimony. I've posted group sizes from my last visit to the range in another thread ("At last - A good day at the range"). I can't see lead in either barrel, though there is still some faint coating of it there - lead removal patches blacken up after 20 passes through the bores. It looks as if properly sized bullets both blew out the ultra-hard foundry type lead, and worked well thereafter.

My MG barrel's bore is at least 0.306 at the muzzle, and a bit bigger at the breech end. Groove diameter is 0.3116 at the breech, 0.3112 at the muzzle. So far it shoots really well if I size to 0.312, and there is no chambering issue because of the way the barrel is chambered. The chamber continues at case-neck diameter (0.3437) right up to the start of the rifling, when it suddenly contracts over just 0.057" total lede length. Hence I can chamber just about anything imaginable. I'd like to try sizing to 0.313 to see whether there are any advantages over 0.312, perhaps at higher muzzle velocities, but so far I haven't managed to buy the right sizing die for my lube sizer. I'm using bore-rider bullet designs in both rfiles. In the 30-30 the nose is just below bore diameter, and in the 30-06 it's 0.001 - 0.002 above bore diameter. I've lapped the 30-30 bullet die to increase the nose diameter but haven't tried it yet.

At the moment I'm pretty confident that the leading in my MG barrel happened because I shot a hundred or two of 0.310 bullets through a groove diameter that was over 0.311. If I'd been shooting any normal alloy it wouldn't have mattered much - I'd have cleaned out the lead and experimented. I had a hard time over the whole thing because what I'd done had effectively lined my barrel with a super-hard substance. That foundry type is mean stuff - it doesn't show marks after being chucked quite hard in a four jaw lathe chuck.

Geoff

[Char-Gar]

Grumpy... I have never used foundry type and after reading your post, have resolved never to do so...sound like the alloy from hell!

For my "big fat 30-30 MG", I had Mountain Molds make my own version of the "fat 30" group buy. The nose tapers from .304 to .307 and the bottom half engraves on the rifling when chambered. Shoots quite well.

I really like these Marlin 30-30 rifles but with the wide barrel specs, they can present a challenge with cast bullets. Sounds like you got yours whipped.

Good shooting...

[Sailman]

This past Wednesday I went to the range to do some more testing. My goal was to see if .310 sized 308-165-SIL would shoot smaller groups than bullets sized
.309.

The testing was done on a standard military Springfield 30-06 in a match grade stock, glass bedded, commercial trigger, barrel was free floated, and the rifle was equipped with a scope.

In my pervious test I shot bullets sized .308 and .309, with 4227 powder charged 13, 14, 15, and 16 gr. For this test I would use the same powder and charges but with bullets sized .309 and .310.

The following are the results of this second test:

Powder--------.308--------.309 ( 1st )-------.309 ( 2nd )---------.310-----------------------
--------------------------------------------------------------------------------------------------------

13gr-----------3 7/8----------2 7/8---------------2 1/4-------------2 1/2---------------------
14gr-----------3 1/2----------2 1/16-------------2 1/4-------------2 5/8----------------------
15gr-----------3 1/4----------2 1/8--------------2 1/4 *-----------2 7/8*--------------------
16gr-----------4 1/4----------3 1/8--------------3 1/8-------------2---------------------------
--------------------------------------------------------------------------------------------------------
The * indicates that there was a wide shot and the group was measured for 9 rounds. I did not weigh the bullets so an occasional wide shot is expected. However, because of past experience, I also realize that the so called wide shot may be part of the standard group. Further testing will resolve this problem.

What becomes very interesting is whan you view the results by looking at the
.308, .309, 310 columns and then view the results from the 13, 14, 15, and 16 gr charges. As of now, I would assume that the 14gr charge behind a .309 sized bullet is the best load. HOWEVER, the group I got with the 16gr charge sized .310
bullet presents a problem. Past experience has been a teacher and I have learned to NEVER base your opinion on ONE ( 1 ) result.

Next Wednesday I plan to duplicate the 13, 14,15,16 gr charge with the .309 and
the .310 sized bullet.

Sailman