Accuracy problem. Could it be the gas check?

[milrifle]

Bear with me. I'm still fairly new to casting, and although I used to do a lot of shooting and reloading years ago, I was never an expert reloader. Just something I did to save money. My loads always shot well enough to suit me, so I never really 'worked up' a load. They just always seemed to work pretty well on the first try with jacketed.

So, after a long hiatus, I got back into shooting and thought I would try my hand at casting. I'm shooting the Lee C312-185-1R over 26 gr of RL-7 in a milsurp 03-A3. I had been getting so-so accuracy. Pardon the pun, but it was somewhat hit and miss. I had tried several different things, and commited the cardinal sin of changing more than one thing at once. Not intentionally, but just happenstance. Frankly, I don't remember all the details, but my hit and miss accuracy had gotten to be more miss than hit. I blamed it on my 49 year old eyes, wind, glare from the sun, dirty barrel, bad day, whatever.

So one day I found myself scrounging for some bullets to load. I found two small batches of bullets that were left overs. I loaded 20 from each batch and went shooting. Thankfully, I had enough sense to try five in one target and five of the other in another target. There was a distinct difference in accuracy. Same brass, same charge, same OAL, just different batches of bullets. So I tried 5 more of each into their respective targets. Same results. Kept going for the remainder of the 20 round group. Don't laugh at my groups, but one 20 round group measured about 3" at 100 yds. The other measured about 8" at 100 yds, not including the two that missed the paper! This is swapping back and forth between the two bullets, not firing 20 of one then 20 of the other.

Here is what I know about the two batches of bullets:

Good group: ACWW with a fair amount of tin, maybe 10%. BHN 14.3. Hornady copper gas checks. Lubed with an uncooked version of 45/45/10.

Bad group: WDWW with 2% tin. BHN 20.9. Aluminum gas checks purchased off E-bay. Lubed with 'Simple Green' or 'Simple Lube'.

I had gotten away from the large amount of tin and the uncooked 45/45/10 in an effort to get rid of the grey 'wash' in my barrel. I got caught with my pants down on the gas checks. When I ran out of the Hornady's, I could not find any more, so ordered aluminum ones instead.

So, what caused it? Alloy/hardness? Lube? Gas check? To answer this, I loaded up eight sets of 5 cartridges with all the various combinations of air cooled vs. water dropped, 45/45/10 vs. Simple Lube, and aluminum vs Hornady gas checks. Unfortunately, I picked a VERY windy day to shoot and I'm not proud of my group size, but based on the small sample size, it appears that the lube and the BHN are not affecting my group size near as much as the gas checks. I know LOTS of people shoot aluminum gas checks VERY successfully. Do I need to 'work up' another load with the aluminum gas check? I have shot good groups with the aluminum gas check, but I don't know what the other combinations were. I have shot good groups with both lubes, too, but again, other than the one listed above, I can't remember what the other combinations might have been. I was actually thinking maybe water dropping was causing my problem somehow, but my experiment didn't prove that out. Instead it really looks like the gas check is the culprit. But why? How?

[MT Chambers]

On another post i tried to list the things that i play around with until I find the right load, the list was very long, you have not "played around" with things at all. example: Bullet band width, bore ride portion width, seating depth, etc. etc. In fact I try many diff. bullets and find the most potentially accurate bullet, and spend lots of time, trying everything with that bullet design.

[FLHTC]

When the bullet leaves the barrel, the gas needs to escape evenly around the base of the bullet. If the check isn't installed squarely, the gas escapes on one side before the other and shifts the path of the boolit. A weight difference changes the impact point too. I separate mine by the tenth of a grain. The aluminum checks aren't the best by far but without seeing how you seated them, its hard to determine what the problem is.

[Wayne S]

The "thing" I noticed in your comments is that you don't mention what size you are sizing your bullets to ?? and if you "sluged" on in some other way got the OD of the rifle's throat.

[cbrick]

I blamed it on my 49 year old eyes, wind, glare from the sun, dirty barrel, bad day, whatever.

You may borrow my best excuse if you wish. Hiccups, I just couldn't get rid of the hiccups. :mrgreen:

Could be the checks though I've never used aluminum checks. As was mentioned they need to be seated flat and square and crimped firm to stay that way.

Have you tried a slower powder? R-7 is kinda fast in a case that large and a 185 gr bullet is not heavy for caliber but it's sure no lite weight, a slower powder may give better consistency with that boolit weight.

Do you know the velocity of these rounds? I've never found the need to quench my rifle rounds up to 2000 fps, air cooled WW with 2% tin shoots well in my 7mm's and 30's.

You're going to have to first keep good notes, then change one thing at a time and see where the groups start to open up.

Rick

[milrifle]

Not sure about the throat, but the barrel slugs at .3095, if my memory serves me correctly. Bullets are sized at .311.

No doubt I could play around some more and try other bullets and improve my groups, but right now, I'm trying to figure out why I can get a 3" 20 round group under one set of circumstances and a 8" group under another set of circumstances with the same bullet.

[milrifle]

I didn't chrono these particular groups, but the same loads at another OAL were 1790 and 1820 fps.

[Ben]

Aluminum gas checks from Ebay that are what thickness ?

Makes a big difference in how a .30 cal. bullet will shoot.

Does your barrel have copper deposits in it ?

[milrifle]

The checks are .014. No, the barrel has been cleaned of all copper.

[Jim..47]

Rather then trying to figure out why the alum gas checks didn't well why not try for now to work on the ones that are doing better?

Or if you really want to persue this I would drop your charge and slow that bullet way down. Is there anyway to recover your bullets to what they look like.

Also, and very important is to describe the group whether its good or bad. Is it round and kind of looks like a shotgun pattern, or is verticle up and down. A couple pictures would be even better.

[detox]

Maybe some of your gas checks are falling off during flight. Try some better gas checks then seat them squarely on bullet before sizing.

Mike Venturino likes the Lyman 311299 in that rifle. You can order some sample gas checked boolits from http://www.montanabulletworks.com/308_Rifle.html to try to elimenate most of your problems. Then purchase the mould foe that boolit

Pickup the latest April issue of Handloader magazine. It has a verygood article about casting for milsurp rifles. Mike also uses SPG lube and linotype lead for these guns. Seems SPG lube works in most everything.

[milrifle]

OK guys, here are a couple of photos of the groups. The upper was 20 rounds. The lower had 20 rounds fired at it, but only 18 hit the paper.

65483
65484

[milrifle]

I see I didn't answer a question. No, I haven't tried a slower powder. I do want to try that, but kinda want to get this sorted out first.

I understand why some of you wonder why I seem to be more worried about what is wrong than pursuing what is right. I guess the answer to that is, I want to gain an understanding of why this happened, not just do something else. Please don't take this as a refusal to follow anyone's advice. It's just something that is bugging me and I want to figure it out. I appreciate everyone's help.

Jim47, you mentioned slowing the bullet down and also asked about recovering bullets. I think I can recover some bullets, but they will have been shot into sand, so I'm not sure if they will be in good enough shape to tell anything from them. Next time I shoot, I will try to recover some. As for slowing down, what is your theory there? Do you think I am right on the edge of exceeding the strength of my alloy? I have to admit, I wondered that myself. I remember going up on powder loads several months ago and all of a sudden, the groups needed to be measured in feet rather than inches. I don't remember now where that was but I'm gonna say it was at 27 or 28 gr. of RL-7. That was before I had a chronograph, so I don't know the velocity.

[Jim..47]

I guess I would just like to see what a much slower bullet would do. If you do that then try lowering your charge by 10% overall and shoot at least one group with that. What we are trying to do is eliminate the possibilty that the charge is too great for the bullet and or the gun shooting that bullet.

I would also try shooting a group of the J-bullets just as a another test. If it doesn't shoot those well then you need to find out what it does like, slower load, different powder, different primer, seating depth and so on.

We just need to find out what the gun likes before you find out what it doesn't like, mainly your 8 inch group. Then you will have an idea of where to go and also understand why your bad bullet didn't group well.

[Doc Highwall]

Could part of your problem be that aluminum is not as ductal as copper, and the aluminum gas checks are falling off the bullets due to spring back.

I only use copper gas checks and I noticed that some would offer more resistance when sizing them onto the bullets then others from the same box.
Now because I was shooting a soft alloy 30:1 I did not want to bend the bullets or leave a mark on the bullets nose I annealed the rest of them and the bullet sizing went much better and I saw a improvement in accuracy.

I would suggest you get some more copper gas checks and anneal them and take care with your loading and shooting them to establish a accuracy standard. Tweak your load till you are satisfied, then try the same load with some aluminum gas checks and see what happens.

[44man]

I fooled with a friends Enfield and cast. He just had 4064 so I worked some loads. I was down to 1" at 100, a tiny increase opened the group to around 1-1/2".
Then another small increase and WOW, over 10". GC boolit. I was thinking maybe skidding when shot too fast but I never found a speck of lead in the bore.
Could the aluminum check demand a different charge? I guess it could, never tried them.
I admit to not having shot cast in rifles for about 50 years other then BP, spent all my time with revolvers and pistols. I am again a beginner!

[Doc Highwall]

44man, I read your posts with great interest when you give your insights as to what works or not when it comes to handguns, the switch over to rifles is not much different.
What I learned is the alloy hardness and crimp is more important with the revolver especially with the larger calibers due to moment forces trying to unseat the remaining rounds in the cylinder when fired.
You mentioned the need for a harder alloy to resist deformation of the bullet when seating the bullets into the case with the need for greater gripping force. (Correct me if I am wrong, I want to learn)

I have worked in the aircraft industry since 1974 and a lot of the things we made were made from aluminum. When I started I worked as a cutter grinder and most of the tools I ground were carbide for aluminum. It was not for the hardness of the aluminum but because of the abrasiveness of the aluminum on the tools. We also did a lot of welding and hydroforming of aluminum which required a solution heat treat of the aluminum which is a complex process, verses copper where you just heat it up and let it cool and you are done.

Copper being being much more ductal then aluminum is a great benefit in shaping it, along with being easily annealed by anybody. Aluminum does not have the same quality's as copper especially about being ductal which I believe is the root of the problem with using it as a gas check material.

As far as using aluminum as a gas check material I think it will work, but only as long as the dimensions of the gas check and the dimensions of the gas check shank on the bullet are within tolerance, requiring the least amount of swaging of the gas check onto the bullet.

[texassako]

My 2 cents. The Hornady GC crimps on(thicker at the edges) whereas the aluminum I have are merely a friction fit. How consistently can you shoot the rifle? You also say the 45/45/10 left a grey "wash" and you swapped back and forth between loads. Maybe fliers as one lube cleaned out the other or the wash? I have been developing loads for several rifles lately and try finding a load for a given lube/alloy/GC combo at a time. One variable at a time is enough for me, and I have accepted that my eyes usually are worse than my open sight rifles' accuracy potential.

[FLHTC]

Photograph your bullets and post those. If you can get close ups, show those and of the base.

[44man]

Doc, that is right.
I wonder if aluminum checks will split when engaging rifling?

[cbrick]

Doc, that is right.
I wonder if aluminum checks will split when engaging rifling?

Yes, I also think Doc hit on an important aspect of aluminum checks. I don't know if they would split but all of the aluminum checks I've seen were much thinner than Hornady copper checks which the shank was designed for. How tight will they be "crimped" on, maybe a better question would be are they any more than a slip fit. Next, would such a thin aluminum check protect the boolit base or being so thin would they allow the boolit base to deform and the check simply conform "mold" into any deformity of the base caused by pressure?

I dunno, just thinking out loud.

Rick

[Larry Gibson]

I doubt it's the alloy change but if getting a "gray wash" with either alloy its the lube that's the problem. Suggest you try straight LLA following the directions.

The flyers could be from the reasons Doc mentions. Could also be the change to speed green lube...........I see the load is 26 gr RL7? At that level the aluminum GCs should work if the are a tight fit on the shank after sizing and the base is squarely seated. If using the COWWs +2% tin bullets lubed with straight LLA and the aluminum GC seated tightly and squarely solves the problem then we know what the problem was.

I see no mention of a dacron filler with that RL7 load either(?) and suggest a 3/4 gr dacron filler be used to posibly improve it if the above works.

Larry Gibson

[milrifle]

I think I may have found it. I pulled the bullets from a few loaded rounds and the gas check stayed in the neck on most of them. The ones that did come out with the bullet, could be pulled off with my thumbnail. Same with some unloaded bullets, as well. I measured some bullets and found the gas checks at .313 and the bullet at .311. Looks like they are indeed springing back. I know that some are making it to the target, but maybe not all? One coming off in flight would certainly cause an accuracy problem, I would think.

Now I can either read up on annealing aluminum gas checks or just go back to the Hornady's, since I have some now. I kinda hate to let the aluminum ones kick my butt. I may have to go back to them one day, if the Hornady's continue to be difficult to find.

Thanks for all your help, guys.

[303Guy]

Something to bear in mind is that aluminium is not simply aluminium - it's an alloy. I know about the abrasive nature of aluminium. I've had to disassemble an aluminium swarf granulater and the wear on the hammers and suction impeller was horrendous! Which is why I never tried aluminium in my bore. One should remember that sand paper is made from aluminium oxide and aluminium always oxidises when exposed to air which mean it always has an oxide layer on it. Anyway, not all alloys are equal and all alloys of aluminium have some heat treatment properties which varies quite widely. The fact that it works for some means that it can work so don't throw them out. But they may be tipping the load over the edge. I'd suggest lowering the load to see what happens and better yet, change to a slower powder.

I wonder whether aluminium would work better with blunter rifling? As per 44man's suggestion that the checks may be getting split by the rifling.

[Doc Highwall]

I agree with you 303guy about what you said. Another thing is the thickness of the aluminum stock you are working with.

I do not think the rifling will do anything as it is only .003" to about .005" max in most cases.

Most of the damage will be from cold forming when making them, and the more steps you have in making them, the more likely you will cause stress cracks where the base of the gas check meats the rifling on the edge of the aluminum gas check.

[44man]

303, good answer. I worked for the airline 42 years and plane skin cracked. It starts at a rivet or screw. The crack has to be stop drilled and a patch put over. I seen a few 737's with four layers of patch. The metal is strong but brittle.
Aircraft aluminum does not oxidize easy unless exposed to salt air or exhaust. It would be the worst for a boat so they make marine aluminum that is still brittle and would not work for a plane.
Pure aluminum is not used for much, it oxidizes too fast and is not strong. The oxide sure will cut steel.
Lee uses a soft aluminum for molds and it can be cut with lead under the sprue plate. I have been using scrap aircraft aluminum for my molds and it is the very best so far. It takes heat, is strong, and shows no oxidation. But if rolled thin and subject to a funny force or vibration, it will crack.
Copper or a bullet metal alloy is still the best for a GC because nobody knows what is in the aluminum.
I do not want to sound harsh but is making checks from a beer can to save money and to make a fellow that makes the tools rich the best way to go.
The man that makes the tools should use copper, better is bullet jacket alloy. He has tried to reduce the price for many but I will always ask if it is the best way. We might get some good tools but where do we get good metal the right thickness?
If you make the tools, supply the correct alloy of copper too.
It like the old days when swaging bullets, buy jackets dirt cheap, buy lead wire dirt cheap and a wire cutter. Never let us look for our supplies. Should not the tool maker sell the proper materials to make the checks?

[Case Stuffer]

Even top quality deep draw aluinum has a shelf life and the more it is worked the harder more brittle it becomes .

One of the things I did during my 40 plus years as a Tool & Die maker / machiney designer / builder was the manufacturing of Expander Metal lines used to produce fairly fine diamond patern expanded aluinum such as was used on the 8-12' satilite antennas for many years. If we ordered coils of material to far in advance or a supplier tried to pawn off old stock on us it was extremely difficult and at times impossible to use it without have numerious breaks in the pattern. PArt of our quality control was cuttin a sample from each delivered coil of material (8 to 10 K Lbs. ) and checkin hardness on a Rockwell hardness tester.

Using a wax drawing compound when drawing the aluinum helps a great deal but was not all that practicle in an expanded metal operation due to the fact that we we running the presses at 600 strokes per minute and consuming 3' wide coil around .032 thick .

[44man]

Even top quality deep draw aluinum has a shelf life and the more it is worked the harder more brittle it becomes .

One of the things I did during my 40 plus years as a Tool & Die maker / machiney designer / builder was the manufacturing of Expander Metal lines used to produce fairly fine diamond patern expanded aluinum such as was used on the 8-12' satilite antennas for many years. If we ordered coils of material to far in advance or a supplier tried to pawn off old stock on us it was extremely difficult and at times impossible to use it without have numerious breaks in the pattern. PArt of our quality control was cuttin a sample from each delivered coil of material (8 to 10 K Lbs. ) and checkin hardness on a Rockwell hardness tester.

Using a wax drawing compound when drawing the aluinum helps a great deal but was not all that practicle in an expanded metal operation due to the fact that we we running the presses at 600 strokes per minute and consuming 3' wide coil around .032 thick .
An expert speaks and all of you should listen. Is aluminum the best GC?

[sthwestvictoria]

Good group: ACWW with a fair amount of tin, maybe 10%. BHN 14.3. Hornady copper gas checks. Lubed with an uncooked version of 45/45/10.

Bad group: WDWW with 2% tin. BHN 20.9. Aluminum gas checks purchased off E-bay. Lubed with 'Simple Green' or 'Simple Lube'.



Could it be the lube? Below are two recent groups, the only difference is the lube:
65668
They are identical other than lube - 19.0grains AR2206H (H4895), CCI LR primer, 150grain Lee FP, aluminiumGC, sized .311, shot at 50metres.
I will say the 45/45/10 is not actually made with JPW, instead a carnuba paste furniture wax made in Australia.
What I am preparing to do is shoot some for comparison with straight LLA, these are drying now and I'll try them against the pan lube ones again. Pan lube is Bee Wax/Petroleum Jelly/Lanolin/Crayon.
Bores were clean with both.
The 45/45/10 has been working well with some very much more low velocity loads of 11.5grains of TrailBoss in the 35 whelen under a 158grain plainbase and in the Win 1984 with 7.0grains Trail boss and the little Lee 314-90-SWC

addit: the elevation is wound up slightly on the 45/45/10 target but that doesn't explain the increased group size.
These aluminium checks stay on to the target - I find them in my boolit trap. These are the sageoutdoor checks that someone gifted me.
Addit, addit: The tighter group is only 4 rounds, for some reason all I had in that loading, normal 5 round groups.
Despite the slight difference in picture sides, the two lower edges of the triangle are both 4".

Last Addit: There is a retraction to this post, see below.

[303Guy]

Very interesting pictures. One can clearly see the yaw in the second picture with the different lube. Curiously, the top two impacts are straight and form a similar group size to the those in the firsts pic.

[Doc Highwall]

Another thing I forgot to mention before about aluminum is we had a job that called for it to be riveted. The rivets had to be annealed and then kept at minus 40 below zero until they were used, and could only be at room temperature for a couple of hours, and if they were kept out longer they would have to be re-annealed.

[Doc Highwall]

I can see the need for aluminum gas checks if they was a shortage of copper like there was in WWII, but I would stock up on copper gas checks now long before I would need them, kind of like the 22Lr. shortage is happening now.

Better to be proactive then reactive.

[sthwestvictoria]

I went out and reloaded again with the pan lube, straight LLA and the 45/45/10:
65867
All the same except for lube - winchester cases, 19.0grains 2206H, 150grain GC, CCI LR primer.
Left to right is 45/45/10 , pan lube and Lee Liquid Alox (undiluted)
I don't think there is much in it.
The 45/45/10 group measures 1 1/8, outside one hole to inside of farthest.
I feel the high shot from the panlube is the a flyer, my best group I have shot with that combination is 1 1/8", this group is 1 1/2" if you discount the flyer.
I did not call the high shot in the LLA group so I think it is a real shot.

So I retract my post above, I can't explain why that group opened up so much with the 45/45/10. I suppose now I need to shoot it all a third time to see which is the most correct grouping.

[texassako]

I was reading the NRA cast bullet handbook last night off the castpics site and thought of this thread when reading the chapter on gaschecks. They tested Lyman and Hornady GCs with everything else exactly the same and had a change in POI. Aluminum is a lot different than the test's brass vs. gilding metal.