How to reduce free bore in No1 Mlll*

Hi everyone, im a new member from tassie (south island of australia), an need some help. I have Lee enfield No1 Mlll* that I have turned into a sporter, ramline stock etc. and have started reloading using 125 grn sierra pro hunter projectiles. The problem i have with this projectile is the loss of velocity caused by the amount of freebore and gas bypassing the projectile before it can engage in the rifling. The reloading data in the manual im using suggests I should be getting around 2900 fps but I estimate im only getting between 2000-2200 fps. Can some one give me some advice on if it is possible to have the throat shortened to help with this problem.

How good is your gunsmith? The only good way to do it is to remove the barrel, shorten it from the breech end(both rear of the barrel and breech step), re-install the barrel and recut the extractor slot and ream the now shortened chamber to the correct size.

The throat is eroded from the use of cordite. Jona's idea will work but it might be cheaper to acquire a new barrel and rebarrel it.

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Originally Posted by Brian Dick

The throat is eroded from the use of cordite. Jona's idea will work but it might be cheaper to acquire a new barrel and rebarrel it.

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It is quite likely the throat is eroded as Brian has said.

One question, though... are you using commercial brass that hasn't been fire formed in your chamber yet?
The reason for asking, the shoulder in the chamber can be quite a way from the shoulder in the case, especially a commercial case. This leaves your projectile even further back for the first firing, but as long as you only neck size there after (or use an adjustable FLR die set to only just touch the shoulder) it will from then on remove that gap from the equasion as long as you are setting your projectile by seating depth and not OAL. Might be worth a try with a couple of second reloads and a chronograph.

The 123gn projectiles are to short unless you seat them as far out as possible then they could still be to short. Have used many but gave them away as a bad idea. The 303 is not a varmit calibre/rifle i tried. 150gn are minimum weight just, 170/215 best. Cordite worn barrels need longer projectiles. Unless you use a chronny your guess to velocity maybe way out the 123gn is light and the pressure will be lower depending on powder used.

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Originally Posted by jona

How good is your gunsmith?

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Thanks Jona for the reply. Thats what I was thinking but I don't know if there is a std. throat length the gunsmith will cut back to or do I give him a dummy round to measure and take it from there. If he cuts too much off does that mean I cant use longer projectiles? I had had the rifle checked for headspace etc. and the report that came back was the rifle is servicable, but in doing his checks he removed the scope and when he replaced it buggered the screws. if a gunsmith cant do up screws with out damaging them how good is his other work?.

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Originally Posted by Son

One question, though... are you using commercial brass that hasn't been fire formed in your chamber yet?

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Thanks for your reply. I started off using mil. surp. but decided to start reloading. Because I dont use heaps of ammo I use a basic setup. My set up is a lee loader (neck size only) with a converted drill press and this works a treat.
I am using remmington brass , 42 grns ADI 2208 powder, sierra 125 grn projectiles. To fire form the brass I cut the load back to 39 grns for the first firing. I dont have a chronograph but my rounds are 2" high at 100 mts then 2"low at 180 mts and i worked backwards using a ballistic table and came up with the velocity of 2000-2200 fps

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Originally Posted by tidesout

125 grn sierra pro hunter projectiles. The problem i have with this projectile is the loss of velocity caused by the amount of freebore and gas bypassing the projectile before it can engage in the rifling. The reloading data in the manual im using suggests I should be getting around 2900 fps but I estimate im only getting between 2000-2200 fps.

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A velocity loss of 700 FPS in less than half an inch is hard to imagine. Your manual suggests 2900 FPS but you ESTIMATE that you are getting 2000 FPS to 2200 FPS. First of all, a Manual is only a generalized guide and the velocity reading will vary depending upon firearm used, barrel diameter, barrel wear, primers, cartridge case, and other factors.

You should run some of your reloads through a Chronograph and get some true readings before you do anything else. How did you come up with your ESTIMATED velocity? I would fire and chronograph your loads in at least two other .303 rifles to get a good idea of what is happening.

Next. What is the actual diameter of your 125 grain projectiles. Are you using .308 inch diameter projectiles designed for the 30 calibre bores such as 30-06, .308, etc. or are you using .312 inch diameter bullets designed for the .303 British?

What is your accuracy? It does no good to have something going like a bat out of hell if you can not hit anything with it. I have used 123 grain Remington bulk bullets designed for the 7.62x39 Russian cartridge out to 600 yards with good results.

What is your actual load? Powder, charge weight, case, primer, overall length?

I believe you should do some more factual testing before you try to fix a problem that may not exist.
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Tidesout, you stated your rifle has a scope, does it have a sporter type forend? If it's still in full military trim there's a lot more to consider when setting the barrel back. Your gunsmith will have to determine exactly how much he will need to remove from the shoulder to get a full turn or two, it has to be exact or the sights will be off to one side. In doing this you are shortening the barrel from rear and this will through off a lot of critical dimentions. As stated earlier, light short bullets very seldom work well in military rifles because even a new barrel will have a long throat. When the manual says a certain load will produce a certain velocity that does'nt mean all rifles of that caliber will produce the same results, thats just what the test rifle achieved. Some rifles have ''slow'' barrels for some reason or another. Have you slugged your bore to determine the diameter? If it's oversized and the bullet does'nt ''fatten up'' to create a seal then it will have blow by and velocity will suffer as a result so setting the barrel back won't solve the problem. Like Brian said, rebarreling would be a better option.

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Originally Posted by tidesout

when he replaced it buggered the screws. if a gunsmith cant do up screws with out damaging them how good is his other work?.

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really pertinent question. he doesn't have to be a bad person either, just not the best with your gun, and perhaps life ...,

I think the boys nailed it, bullet is too short compared to a 174 or 150 grain,
My 2 cents = try heavier bullets and observe if problems still exists, use a chronometer,
Then reload with 150grains, using larger diameter bullets to match the wear on your bore.
If you want speed of light varmint type shooting you could always try the classic and well proven 303-25 and there's other wildcat sizes out there too, etc, thats a big case driving a small bullet very very fast, 3240?
Or, a new barrel ...
but do not shorten it the way you're thinking, try everything else first.
Don't use boat tails on a worn barrel = keyhole issues.

and btw, welcome to the forum, for links to absolutely everything enfield try enfield resource.com

Or, if velocity is your goal, use a sabot bullet ( see Sabots, sabot, sabot slugs, sabot rounds, sabot ammo, sabot reloading, sabot results, sabot pictures, sabot ammunition, sabot ammo, sabot starter kit, sabot projectile, sabot bullets, shooting reloading, hunting reloading, reloading components, reloading ammunition, varmint hunting).

If you want to establish the maximum bullet length and size that you can sensibly use in your rifle, please take a look at

Refurbishing an Argentine RB - Part11

(Restorer's forum) - which provides a detailed description of a method that can be applied to any bolt-action rifle. In particular, it illustrates that a too-short bullet causes insuperable problems.


Basically, I suspect (like others) that you have created your own problem. The Lee Enfield No.I MKIII was not designed as a varmint rifle, and there is no point in trying to turn it into one.

Follow the method outlined in the contribution mentioned above, and you will quickly have something that works as well as the rifle (and the "driver"!) will allow.


Patrick
:wave:

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Originally Posted by Patrick Chadwick

The Lee Enfield No.I MKIII was not designed as a varmint rifle

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[Hi all Thanks for the replies. I have obtained some 180grn projectiles and these work a treat, so the 125 grns are banished to the back of the cupboard (unless someone else wants them )

tidesout

Good to hear of the improvement with the 180's!

Not sure whose loading data you are using, but AR2208 (ADI) is WAY too slow for 125gn bullets in a .303, good with stiff loads behind the 180's, though.

AR2207 will work much better, AR2205 is a bit quick.

I did some experiments with the military 123gn projectiles from 7.62 x 39 ammo about fifteen years ago. They group "reasonably" and you can make them go REALLY fast. However, they have a radically different point of impact from 150 or 180gn bullets. I also tried some Remington sabots with 55gn bullets driven by, I think, AR2205. Unfortunately, my old load data card file got lost in a move. It's probably mouldering away under a bunch of as-yet unpacked bric-a-brac.

I had the same problem. I found Hornady #3130 bullets did the trick.
B

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Originally Posted by Bruce_in_Oz

I did some experiments with the military 123gn projectiles from 7.62 x 39 ammo about fifteen years ago. They group "reasonably" and you can make them go REALLY fast. However, they have a radically different point of impact from 150 or 180gn bullets.

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I've played with pulled 7.62 x 39's also, with the same basic results as yourself. It may be relavent to note that the FMJ bullets share the same basic dimentions as a 150 grain bullet, so would be closer to the rifling than a 125 gr. copper jacketed bullet which is physically smaller in dimentions.