Using .308 projectile, in a .303 brit

mosquito99

mosquito99

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Im wondering if using a .308 in my .303 custom will help with accuracy. The grouping with factory 180gr federal ammo is not bad but could be better, and about every 5 or 6 round ill get a flyer thats 3 or 4 inches out of my pattern. Now i have caught a slug and measured it, and its .309, would i be better for my rifle to try .308 projectiles becasue im so tite in the barrel. the barrel is an summer set barrel is that helps
 
I've had mixed results with this sort of thing in the past, and Grizzlypeg is completely right; just try it out. I've had .303s that wouldn't shoot worth a darn with .308 bullets, and others would shoot like magic with only .308 bullets. Depends on the barrel.

Erik.
 
I've heard that if you use bullets with exposed lead at the base and a relatively quick powder the bullets will "bump up" to bore size and be more accurate. Bullets with exposed bases you might try are partitions and hornady fmj's...
 
thanks for all the input guy and i think ill give a try, and beside if i use .308 projectile it greatly improves the variety of projectiles i can use.
 
I've said it before and I'll say it again... the best 303 british is one that starts out as a 30-30 and then gets a reaming to 303 british (308 british?) .311 bullets are a PITA - I think mostly because they are so darn close, but not quite and it just pisses a guy off that he can't use his stash of 30 caliber boolits in an enfield.
 
If you are looking for accuracy you should stick with .311 - .312" bullets. The best accuracy all around that I have found came with Sierra "MatchKing" bullets in that size. Taking the opposite angle here.....I have a Savage 1899 "B" that won't shoot .308" bullets worth a darn but will shoot those .311" MatchKings into a very small group. No, there were no signs of pressure either. So, if you have a 30 caliber rifle which has a worn bore try this. I started with reduced loads and worked my way up with no indications of any problems. Dave
 
"...think ill give a try..." Slug your barrel. Lee-Enfield barrels can measure from .311" to .315" and still be ok. A .308" bullet in a .313" barrel will rattle down the barrel and give very poor accuracy.
"...Savage 1899 "B" that won't shoot..." Sounds like a worn out barrel.
"...starts out as a 30-30..." A .30-30 uses a .308" bullet. Totally incorrect case. The rim is far too small(34 thou smaller), as is the case length(180 thou shorter).
 
sunray said:
"...think ill give a try..." Slug your barrel. Lee-Enfield barrels can measure from .311" to .315" and still be ok. A .308" bullet in a .313" barrel will rattle down the barrel and give very poor accuracy.
"...Savage 1899 "B" that won't shoot..." Sounds like a worn out barrel.
"...starts out as a 30-30..." A .30-30 uses a .308" bullet. Totally incorrect case. The rim is far too small(34 thou smaller), as is the case length(180 thou shorter).
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the barrel is not an old millitary barrel, its new . i have less then 200 round down the pipe, i need to slug my barrel, but i have measured it and the mussle and it measure .309 in the rifling grooves, at 25 yards i get a about a 3 inch pattern at 100 yards its way worst 8-10 inch depending on the how many shots ive fired and how hot the barrel is, and it get real hot. i put 70 factory winchester 180 gr buulets down it yesterday, barrel was so damn hot i couldn't touch it. was just thinking of why its all over the target, is cause the barrels is so tite,
 
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Even with exposed lead at the base, a bullet like the partition, will not slug up to fill the bore, only relatively soft cast bullets will do that, that's why the most accurate cast bullets "at higher speeds" are .001 or better still .002" over bore size.
 
I think the op put a new .308 barrel on chambered in .303 brit & has been shooting .312 bullets through it. Try the .308 bullets see what happens.
 
wouldn't it be nice if there was a $10 die that you could screw into the top of your reloading press to bump 308 bullets up to 312 or so....
 
Just did a little research: here's what corbins dot com has to say:

Sometimes, a person wishes to "bump up" a smaller commercial bullet to larger diameter, such as making a .311 bullet out of a .308, or a .228 bullet out of a .224. While this is possible, the results usually are not quite the same as making a bullet by properly swaging it in a 3-die set. Putting the undersized bullet into the larger point forming die is the same as using an undersized core seater die: you get the same kind of taper, bulging, and other problems that would not occur if the bullet were swaged from a core and jacket. The pre-existing ogive and nose shape have an effect on the operation, as well, so sometimes it works reasonably well, and sometimes it doesn't. We can provide the point forming die to use as a "bump up" die for jacketed bullets, but we cannot guarantee the results. This is a "try and see at your own expense" proposition, because whatever bullet you choose to bump up will have an effect on how well it works...even the same diameter and weight and shape of bullet from a different manufacturer or different production run can have enough difference in its jacket hardness, thickness, core material, and other springback factors so that the diameter and taper are different, using the same "bump up" die.

The good news is, that the same point form die you order for "bumping up" a bullet will be the same one you need later if you decide to do it right and make your own bullet. So, it isn't a waste of money. You can just add the core swage and core seater, and swage excellent bullets of the proper weight and diameter.
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i used to have a no4 mk1 rechambered to 303 epps. it was of savage manufacture with a 2 groove barrel. with 311 speer 180 hot cores it would often group under 1". i then tried 308 dia 180gr nosler partitions. and it grouped around 1 1/2". the barrel and action were in excellent condition and the bore slugged 310. it is definetly worth trying 308 dia bullets especially if you want to use a premium bullet it may shoot fine.
 
sunray said:
"...starts out as a 30-30..." A .30-30 uses a .308" bullet. Totally incorrect case. The rim is far too small(34 thou smaller), as is the case length(180 thou shorter).
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He's not saying to try to use a .30-30 case. He's saying that the .308 bullet, loaded in a .303 case, starts out as a .308 and swages up to a .311. Seemed pretty clear to me. Pull your head out and start again.
 
Sluged the barrel

well i took the time to slug the barrel, and it measures out .298 and .309 repectively it has 2 groove rifling. I also took the time to load 40 rounds with .308 180gr hornady interlocks,with 42 gr reloader 15 powder. it was better then factory winchester 180 for accuracy, i was only able to get off 5 rounds before i had a technical difficaulty(had a miss fire). I was able to get the slug out once i got home, i didnt have a rod with me. So i will try agian next weekend. i love this new to me hobby, i have even more excusses to fire off my guns
 
mosquito99 said:
well i took the time to slug the barrel, and it measures out .298 and .309 repectively it has 2 groove rifling. I also took the time to load 40 rounds with .308 180gr hornady interlocks,with 42 gr reloader 15 powder. it was better then factory winchester 180 for accuracy, i was only able to get off 5 rounds before i had a technical difficaulty(had a miss fire). I was able to get the slug out once i got home, i didnt have a rod with me. So i will try agian next weekend. i love this new to me hobby, i have even more excusses to fire off my guns
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Sorry to hear about the misfires... but the good news is that the barrel appears to be a candidate for accurate 308 bullet loads. Keep up apprised of the group sizes if you can.
 
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