Question about size

[math]

Hi
I'm trying to get this 420gr LBT spitser to shoot but it's not going so well :(
Herse my setup:
Bore measures 11.052mm
Bullet measures 11.09mm
Gaschek and lubed with LBT soft blue
I'm starting to thik that my bullets are to big.
Any thoughts are welcome
Regards Math

[felix]

Centerline of gun and ammo must be a straight line before (and after) firing. This is much more important for spitzers than for wadcutters. ... felix

[BABore]

And during firing.

Your only 0.038mm or 0.0015" over groove. You said bore, but I'm assuming you meant the groove diameter. When I said during firing I mean what happens as the case neck expands against the chamber wall. The boolit is still in the case at that point or close to it. Measure the inside diameter of a fired case. Cases usually spring back approximately 0.0254mm or 0.001" per side after firing. A boolit that will just slip into a fired case will have plenty of room for safe firing but not give the boolit too much wiggle room so it can cant. Now look at the throat area. Will a boolit this big chamber in the throat. You actually want some light engraving. A big throat diameter ahead of a normal case neck diameter is problematic. The ideal situation is to partial size the case so it's centered in the chamber and in line with the bore. Fill the case neck and throat with a big enough boolit so canting doesn't occur. Lightly engrave in the throat and start of the rifling or bore depending on the boolit nose profile. All of this will create a situation that Felix is talking about. The barrel does a fine job of sizing the boolit down to fit, after it gets there straight.

If all these conditions are met, and it still doesn't shoot, look to your alloy, lube, and powder. The LBT lube your using is a great lube. It can also cause fits at times. It's very slick and not much is needed. Boolits with lots of lube capacity can leave excess lube in the bore and cause flyers. Especially after a break when the bbl is allowed to cool down. LBT is also know for shooting badly when temps drop below 55-60 F. Partially lubing the boolit or switching to a simplier lube may be needed. Not all alloys will shoot the same. I prefer lower antimony alloys with just enough present to harden the boolit to the level I desire which is around 20-22 bhn. You can try them air cooled and water dropped for comparision. Antimony can become a fouling issue, so the less the better in most cases.

[math]

Some more info on my bullet and how i have been loading it.
They are cast from WW alloy and waterquenched.
My cartridges are made so that they are 0,1mm shorter then max length
Yes my bore measures 11,052 in the grooves ( where she is biggest)
A caliberd bullet will enter a spent cartridge whit some sucction
I hope you all understand me even thou english is't my first language :)
Thanks for the help.

Here's a picature of the bullet in question
http://i244.photobucket.com/albums/gg21/mathias1978/P3310001.jpg

[BABore]

What velocity are you shooting for? What is your current group size? Yardage? # of Shots? Sighting equipment? What does a known accurate load group in the gun.

[405]

I understand the partial language barrier- no problem. But, I'm not exactly sure of the cartridge/gun type or your goals of velocity and pressure? And, that bullet looks like a very good/stable design.

Is the nose a true bore rider? If you seat the bullet well out... do you see land engraving on the sides of the nose? If not then the bullet nose diameter may be a little too small. That leaves the shank (drive bands) as the only surface that will keep alignment as it starts down the bore. You might try seating the bullet far enough out so that some portion actually touches/shows engraving on the leade or lands. As has been suggested.... longnose bullets like that need as much alignment help as possible so they get started into the bore "straight" and stay straight as they travel the length of the bore.

Your basic sizing diameter, alloy and lube should be ok and probably not the major cause of inaccuracy. If I were loading that type of round I'd seat the bullet out far enough to contact the lands or leade and use a powder similar to 5744 or 4759 loaded for a muzzle velocity of about 1000-1200 fps to start with... in other words a blackpowder similar load.

Hope that is not off the mark too far-

[math]

Ok let me see if i can answer som questions
The cartridge i'm loading is the .425 westley richards.
the distans i'm shootig at is 80m, i'm using a good rest, hand beetveen support and forestock and a Leopuld 2-7x33 , set on 7 whwn testing for groups.
http://i244.photobucket.com/albums/gg21/mathias1978/P3310001-1.jpg

this is the groups i have come to expekt from this rifle, Those grops was made with a 375gr sp with a jacket made of copper tubing, V0 706 ms, shoot at 80m.

I was hoping to be able to shoot leadbullets at somevere beetveen 550-600ms.
My start load was 60 gr Norma 203-B and that gave a V0 594ms and a lot of lead have been backing my load in 5gr increments and is down to 50gr now but have not been able to shoot it over a chronograf, but it still leads badly. For a test i make sure that the barrel is clean, i make 5 rounds of the load i'm testing, what i have seen is that there is wery little lead in the barrel after shoot 1 an shoot 1 and 2 touches then there has been a jump of some 3-5 cm to were the next shoot lands and so on, groups have ended up somevere beetveen 15-20cm.

The bullet is not a nose ride, all the cylindrical part of the bullet is grove diameter. I'm seating the bullets 0,1mm from tuching the lands,

Hope that was some anwers to your questions, thaks Math

[405]

OK got it- 425 WR. Pretty big boomer beltless mag design with fairly shallow shoulder angle. Do you think the lead build up is causing the accuracy problem or something else? If it builds rapidly it will degrade accuracy- even over a 5 shot string. Also, since that is not a bore rider nose and may be seated fairly deeply...... does the base/gas check protrude into the body of the case when seated?

I'd still drop down to a lower velocity/pressure. And, seat the bullet out farther if the base is into the case body. Just touching or engraving the leade and using a powder suitable for the reduced loads would be worth consideration. I see that Norma 203B is in the burn rate range of powders like Reloader 15 and Varget. The Scan. powders from your area that seem to be in the burn rate range I'm thinking are VihtV N110 and N120 and Norma 200. To achieve the lower velocity/pressure range of 1200 fps in the big case you might also consider a low density filler of dacron/polyester.

[math]

My gut fieling tells me that accuracy goes south becuse of leading sence the 2 first rounds toches, but what i going to do before i continue whit leadbullets is to check my scopemount, it's a Apel turnmount so nothing has gone wrong there.

The bullet does not down in to the case.
Math

[303Guy]

If I may make a suggestion - try using a slower powder and use wheat bran as a filler which gets slightly compressed by the boolit when seated. The wheat bran acts like a wad and cleans the bore with each shot. It does not raise the pressure a lot but do allow for that.

[nanuk]

Math:
do not get discouraged
There are some VERY intelligent shooters on this forum
With patience, and trying their advice, I believe you will see improvement

[Bass Ackward]

Well I look at that BIG drive band with no lube on it and I get scared just looking at that. Did you wait long enough for the bullets to harden properly? This can take up to 30 days with some batches. Use your finger nail to try and see any mark. If you can, then they aren't hard yet.

First I would clean well. You are going to need to clean mechanically and not chemically. I would go so far as to use a fine steel wool on a bronze brush. All the lead must come out. Then clean one time chemically. If you have a clean patch move on.

Then I would put some lube on a patch and patch it in the bore to start. I would rub the WIDE drive band with the lube on the patch you just used.

Then I would load a few squibs with fast powder. Just enough to push the bullets out the bore. If you can't see flies landing on the bullet, then it is too fast. This is to prepare the bore. This is also how you remove lead in the future. Shoot slowly to avoid heat.

Then I would start back with your 50 grain loads and shoot several. Maybe 20 and observe the bore as you go. Then if there is no leading, start working up from there, but as others have suggested, you may need a slower powder if you want more velocity. If you have no lead, save the brush for when you clean again in 40 or 50 years.

[math]

The bullets have spent some 7 months in a cabinet while i was in Afghanistan and i can't scratch them with my nail.

All my hunting is made with jacketed bullets so this was just for fun and ofcourse to bee able to shoot mor but i do not know if i will bee intrested in going thro the truble with fillers and stuff.

I have some other powders thar i can try, AA 4350, Norma 204, Norma MRP and Trail Boss.

Any thoughts on which would bee best worth a try ?

Many thanks for all the help so far
Math

[Bass Ackward]

Well, I can tell you that if you apply logic that the best powder to try is _______________.

But the truth is that the gun has to tell you that. And the logic isn't like jacketed.

I generally find the best luck with a powder that is 2, IMR burn rate classes below the powder that produces the highest velocity with that weight bullet in jacketed.

In other words, lets say that the highest velocity was with 4064. Then I would go with 4350 to start. I always do better with full cases of powder.