Problem with cast Rcbs 180g in M1A

[Ford SD]

Well I have run into a problem over the Holiday season a New Mould
This is a project inline with (Bruce B Cast in the M1a Sticky)

How much nose contact can I get away with in a M1A Clone (Norinco 308)

New mould is a RCBS .30-180-SP 180g cast weight with GC 187.7+-
Overall Length with GC 1.070" Cast dia base .310 nose .302+-

I have been told --
Rounds MUST be free-chambering for these semi-autos, without any restrictions due to land contact, etc.

I have tried a dummy round in a fired case loaded with a cast bullet (chambered by hand) and got a overall length of 2.506 but that means app .180 of the bullet base is below the neck---- Way below the neck, its even with the top of the shoulder
Its some thing I have not done before

When I tried a round with the base even with the bottom of the neck it pulled out of the chamber with the assistance of a finger nail (bullet stayed in brass as in picture with rifling marks)

I have had previous experience with a similar bullet a Rcbs 165g Sil length of 2.715-2.716 (base even with the bottom of the neck)
with very little contact,-- it has a shorter nose and 0.301 dia

How much contact can i get away with ? Zero / a little bit /
I consider the contact shown as a lot (in a semi)

I can not get my rifle to function100% with the 150g or the 165g Rcbs and i have tried 4 or 5 powders and a total of 650 round of cast so want to try a heaver bullet:killingpc

Thanks
and

Happy New year

[BruceB]

"How much nose contact can I get away with in a M1A Clone (Norinco 308)"

NONE....no contact whatsoever

" Way below the neck, its even with the top of the shoulder
Its some thing I have not done before"

This is not a problem...try it and see how the accuracy works out.


"How much contact can i get away with ? Zero / a little bit /" NONE....see above.


"I can not get my rifle to function100% with the 150g or the 165g Rcbs and i have tried 4 or 5 powders and a total of 650 round of cast so want to try a heaver bullet:killingpc"

Try a heavier bullet, or try increasing the charge weight of MEDIUM-speed powders.....or even some slow burners as detailed in the M1A cast-bullet stickied thread. The 150 should work with the right charge level.

[Ford SD]

Did another black marker test with a length of 2.608
bullet base (310 dia) is even with the end of the case

Still a bit of contact about 1/16 of very light contact

will try another dummy tomorrow even deeper but not sure how deep i can go ????

Not a lot of gun smiths around here that could recut the throat if i wanted to go that route ---- and i think it is a chrome lined barrel

or a nose sizing die ???? how do they work ?

[Ford SD]

Thanks Bruce for the work you have done

Powders I have tried with the 150 /165 As cast weight 155 & 172g
are
Sr4759
5744
Imr 4895
h4227

the 150 have mostly never functioned action enough to pick up another round
or can not even put a group on paper at 100yds
My other bolt gun loves 150g lead will shoot all day 50r in to less than a 2-1/2 minus called flyers but shooting a lot slower FPS
the 165 sil for better words act like weather sensitive rounds one day work the next won't
Clothing ??? wearing a sweat shirt to not wearing one just on the verge of working
or groups open up

[BruceB]

Thanks Bruce for the work you have done

Powders I have tried with the 150 /165 As cast weight 155 & 172g
are
Sr4759
5744
Imr 4895
h4227

the 150 have mostly never functioned action enough to pick up another round
or can not even put a group on paper at 100yds
My other bolt gun loves 150g lead will shoot all day 50r in to less than a 2-1/2 minus called flyers but shooting a lot slower FPS
the 165 sil for better words act like weather sensitive rounds one day work the next won't
Clothing ??? wearing a sweat shirt to not wearing one just on the verge of working
or groups open up



Well, lessee here.

In my M1A, 25.0 5744 functions well with the 311466 bullet (152 grains in my alloy). Accuracy is good neough to win the NCBS long-range match, a 16x24 steel plate at 417 yards....100% hits for five rounds, iron sights, sitting, no sling.

Thirty-odd grains of 4895 also works well with bullets from 150 to 200-plus grains....start low and work up gradually.

4227 gave mixed results.

Try some of the slow-burners, too....4831 and 4350 may surprise you.

In some loads which are marginal for function, taking a HARD grip/position when firing will offer a bit more resistance to the recoil pulse, and thus direct more energy to the operating parts. Sometimes this will enable proper function. However, if the load is this marginal, I'd raise the charge a bit to speed the stroke up a little.

[Ford SD]

I have only been using air cooled bullets using WW with a bit of solder added (to get better fill out)
I have some very hard lead, if I put all of in a back pack I could pick it up and carry it so saving it for a rainy day

If I mention my bolt gun and my semi
NOTE
I keep my brass separate marked for each gun in 50 round ammo boxes and load 50 at a time for that rifle.

With IMR/ H4227 using the 165 sil (172 as cast) I did a 1-1/8, 5 shot group at 100 yds the only problem was not picking up another round and when I increased charge groups opened 3-1/8 with a .7g increase
So saving that data for more testing with the bolt gun
I also thought about trimming a old spring to get it to work

With SR 4759 and the 165 sil (172 as cast) when I got it to function brass was taking a beating and groups opened up --- 2 plus grains above what my bolt gun likes another one I also thought about trimming a old spring to get it to work

With IMR 4895 Don't even minion 150g and 4895 in the same sentence
With IMR 4895 and the 165 sil (172 as cast) when I got it to function brass was taking a beating best group was 3" for 5 rounds at 100yds
if I had a good renewable supply of brass and shooting at (50yds) for a fun, THIS would be it

5744 and the 150g a 70 deg. F test day and I did not keep any targets (Bad day) could not keep it on paper
5744 and the 165 sil (172 as cast) one load did do a 4 round 2-1/2 in group (on the horizontal) 1/2" in height ---- rifle not picking up rounds (could have been me)

and if you were wondering I am using a scope for testing

and if you were wondering about my shooting ability on a good day with my bolt gun
(light barrel)shooting cast have done several less than 1" 5 shot groups
on a bad day don't keep targets -- i just have fun

That is why I picked up the RCBS 180g SP looking to get semi rifle to function

and
Yes i realise every rifle is different and one load that will work for one will not work in another and most of people here are using Lyman moulds not RCBS

[Larry Gibson]

You might find the Lyman 311299 to be one of the best cast bullets for the M1A and M1. It has enough weight (200 gr +/-) to allow excellent and 100% reliable functioning with medium burning powders such as 4895, especially if a dacron filler is used or with H4831 without a filler. Velocities are low enough at the 100% functioning range to keep the bullets under the RPM threshold for best accuracy also. Velocity, for the best accuracy, should be held within the 1800 - 1950 fps range for those rifles with 10" twists and 1900 - 2200 fps for those with 12" twists. 100% functional relaibility can be found in those velcoity ranges with the heavier 311299 and medium and slower burning powders such as 4895 and H4831.

BruceB's article/thread/sticky has a lot of good information about loading for the M1A. It is well worth a purview for the info contained.

Larry Gibson

[EDK]

There's plenty of data on 311299 over in group buy results. Snafu12 has been using this boolit in a NORINCO M14 with H335...I have 8 pounds of it sitting in the shack.

I just retired and getting the M1A to function with 311299 (from NOE) is one of my projects IF the weather stays decent. (The path to my 100 yard range downhill from the house is steep AND slicker than #$%^ with a bit of rain or ice; don't need no broken body parts!) If the weather gets tough, I'll cast and then get busy with the STAR and the DILLON 550B in 357 and 44. Sooner or later, I got some berm mining to do also.

:cbpour::redneck::Fire:

[Ford SD]

Just a small add on
Did some more research and reread Bruce's post
Bruce stated he was shooting a Springfield model 9222
went on the Springfield site and that model has a 1:11 twist.
and it might have a long throat barrel ?

My rifle has a 1:10 twist so that is one thing different right off the top.

That also explains some of the bad results with 150g bullets

[SharpsShooter]

You might find the Lyman 311299 to be one of the best cast bullets for the M1A and M1.
Larry Gibson

No argument there :D

http://i146.photobucket.com/albums/r255/SharpsShooter_photos/M1with3112992.jpg


SS