303 British starting load

[Pirate69]

Can't wait to get started. I have some boolits casted but GCs are in the mail. I want to shoot a few rounds but I don't want to lead it up in the beginning. My boolits are casted from wheel weights. Any chance 6.0 grains of Bullseye will give me a problem without a GC? Also have Unique, Reddot and IMR4895 available. Any starting loads for 100 yards or less will be greatly appreciated.

[3006guns]

I'd shy away from Bullseye until you get your feet wet. Don't get me wrong, it's good powder but Unique would be a much better choice, say about 8-9 grains or so without a gas check. This will get you going "boom" and crank up the wow factor a bit until your checks arrive. Do you have any sort of manual that covers cast loads?

By the way, the correct term is "cast"....used in both present and past tense.......no such word as "casted", no matter what you saw on the internet!;)

[35 Whelen]

Can't wait to get started. I have some boolits casted but GCs are in the mail. I want to shoot a few rounds but I don't want to lead it up in the beginning. My boolits are casted from wheel weights. Any chance 6.0 grains of Bullseye will give me a problem without a GC? Also have Unique, Reddot and IMR4895 available. Any starting loads for 100 yards or less will be greatly appreciated.

I use Bullseye in my 7.5 Swiss to the tune of 6.7 grs. with a 155 gr. plain-base bullet. Given this is my 100 yd. match load, I've fired well over 1000 rds. this year and have had no problems at all including no leading. I've also used 7.0 grs. of Bullseye in my '06 with the same bullet. For everything else I use Red Dot almost exclusively. A light load of 8.0 grs. gave good accuracy in my 7.5 and should work in your .303 with the unchecked bullets.
Just be very careful with these light loads. I strongly suggest you turn your cases base up in the loading block after you prime them. Then, weigh and charge one case at a time, and seat the bullet before going to the next. This method virtually eliminates the possibility of a double charge.
Good luck,
35W

[3006guns]

Good reply Whelen......I should have made the point that Bull is good, but only with experience. A mistake can cost you your gun....or worse.

[dualsport]

What boolit? Size? Boolit fit is likely to be more critical than which light charge, in my experience. I agree the above charges are good starting points, probably can't go wrong with any of them.

[Larry Gibson]

Can't wait to get started. I have some boolits casted but GCs are in the mail. I want to shoot a few rounds but I don't want to lead it up in the beginning. My boolits are casted from wheel weights. Any chance 6.0 grains of Bullseye will give me a problem without a GC? Also have Unique, Reddot and IMR4895 available. Any starting loads for 100 yards or less will be greatly appreciated.

You don't say what bullet(?). However 6 gr of Bullseye will probably be a nice load in the .303 without GCs. It is generally the load I use for such.

NOTE: the cautions mentioned above are well founded with regards to a potential double charge. When loading such loads I use one rule for safety; any cartridge standing in a loading block/tray has powder in it. I do not put the cases into the tray at any time during the loading process until they have been charged with powder. I use small boxes (cigar boxes or the small plastic Dillon type) to keep the cases in to keep the cases in during the various stages of case preparation. That way I do not double charge a case.

Larry Gibson

[MtGun44]

10 gr Unique is VERY often extremely accurate with any of the 20th century
milsurp bottleneck rifle cartridges. NOT .30 carbine, although I do not load for it and
maybe it is OK, you'd have to check for that one.

With the big full power milsurps (.30-06, .303 Brit, 8x57, 7.62x54R, etc)
this is often a very good mild accurate load with any weight cast boolit. Start with
.002 or .003 over your groove diameter (need to slug the barrel).

Bill

[Pirate69]

Thanks for the cautions; you can't be too safe.

I am using a Lee CLT312-160-2R mold. This is a GC mold. Do not have a sizing die yet. It appears to be dropping at 0.313". I have slugged my barrels but reading the 5-land barrels is a challenge. The cast boolit is very tight as a slug; so I am hoping that I am close on the unsized boolit.

[longbow]

It is definitely easier to slug the throat that to get groove diameter on a 5 groove! If you size at or very slightly under throat diameter you should be good.

+1 for 10 grs. of Unique. Nice light load and doesn't require a gas check. I use it under a Lyman 314299 at 200 grs. and also plain base at 215 gr.

Longbow

PS: Just had a flash. Go look for the sticky on reloading misurps. There are some good suggestions there and Red Dot is one of the powders C.E. Harris uses for his general purpose load for mid size cartridges like .303.

[Pirate69]

How do I slug the throat?

[longbow]

I used an oversize boolit dropped in from the breech after removing the bolt then tapped it into the throat with a brass rod and mallet (tap not bash). Then use a cleaning rod or other long rod from the muzzle and tap it out. Mike where it was swaged into the throat.

Any piece of soft lead (split shot, lead stick for fishing weights, etc.) that can be cut, turned or swaged to be close to but over expected throat size then tap it in should work. I used an oversize mould at 0.318" knowing that the throat diameter should be somewhere between 0.313" and 0.316". Turns out to be 0.315".

A simple mould can be made by drilling a blind hole in a piece of wood with a 5/15" (0.512") drill bit to cast a slug (the bit will drill oversize). If too loose in the throat bop the end to swell it and try again.

Or you could get some Cerrosafe and make a chamber casting then mike it. If the boolit fits the throat (should just slide in) it should be slightly oversize for the grooves.

Longbow

[corvette8n]

I start all my mil-surp with 8gr of Unique and work up to 10. Check to see how the brass looks after each round.

[Multigunner]

You don't say what bullet(?). However 6 gr of Bullseye will probably be a nice load in the .303 without GCs. It is generally the load I use for such.

NOTE: the cautions mentioned above are well founded with regards to a potential double charge. When loading such loads I use one rule for safety; any cartridge standing in a loading block/tray has powder in it. I do not put the cases into the tray at any time during the loading process until they have been charged with powder. I use small boxes (cigar boxes or the small plastic Dillon type) to keep the cases in to keep the cases in during the various stages of case preparation. That way I do not double charge a case.

Larry Gibson

When using Bullseye to load .38 Special I don't pour powder into a case till I've turned the case upside down and shaken it to be sure I haven't already charged it and forgotten having done so.

[Pirate69]

I loaded 20 rounds of the 160 grainer with 6.0 grains of Bullseye today. Grabbed a #4M1 and a #5 and went out to the farm. I was pleased with the grouping at 50 yards. The No. 4 gave me a 1.5" five shot group and the No.5 a little over 2". Its a start anyway.

I am still struggling with bore dimensions. I took Longbow's advice on drilling a 5/16" blind hole and filling it with lead to form a slug. The bit must have been small since I ended up with slugs 0.311-0.312" Turns out the drill bit did not overdrill the holes. If I wanted it not to overdrill, it would have overdrilled. I think my sluggs will be too small when I try them. Oh well.

[dualsport]

Now that you have fired cases you can tell what size you need by measuring the inside diameter of the neck of a fired case. Go .001" under that measurement. Matching the throat is more important than groove diameter. By matching the throat you start the bullet straighter, it will size down to groove diameter automatically to a perfect fit. IMHO

[longbow]

dualsport is right on. That is probably easier and should do it.

To absolutely confirm throat diameter you could give the slug a bop on the end with a hammer to fatten it a bit then tap it into the throat. That should work and confrim throat diameter.

Alternately you could drill 1/64th larger and recast, then if necessary file a little off on a taper using a drill or lathe if you have one (if you have a lathe, you could turn a slug) so the slug will start in the throat then tap it in. Mike the swaged bit after you get it out.

Longbow

[curator]

I tried several methods to get a good throat slug until Veral Smith gave me this idea: fill an empty fired case (dead primer stil in) with melted lead, up to the shoulder. After it cools chamber it in the rifle you wish to make a throat slug for. Drop an undersize soft lead slug down the bore then using a stiff brass or steel rod and a heavy hammer, tap it to upset it into the throat. When the hammer begins to "bounce" open the breech and tap it out carefully. Your throat slug will be attached to the fired case and give you a perfect impression of your chamber length, throat diameter, and the condition of the leade. 1/4 inch drill rod is perfect for the .303 british.

[Multigunner]

When I slugged my MkIII bore I just used a cast 185 gr bullet, tapped it into the throat and leade using a wooden dowel and then pushed it back out with an aluminum cleaning rod.
After cheacking bore diameters in the leade I checked at the muzzle the same way , then ran a slug from breech to muzzle to check for tight spots. She slugged out at exactly .311 from breech to muzzle, the bevel on the lands at the throat is still sharp and clean, no visible sign of erosion.