Accurate Lt-30 best use??

[DaveH14]

New reloader: I've encountered my first real problem. AR 15- NATO 1:7 twist. Shooting .223 55gr. Hornady FMJ

I purchased 2 lbs of LT-30 because it was what I could get at the time. This powder was one of the suggested powders in my reloading book (Lee second edition) for 55 grain jacketed bullets. Rounds are set at factory length and crimped moderately.
I'm shooting FMJ Hornady bullet with 1.46 cc LT-30 which is (at the start load recommendation). The gun fails to cycle once in awhile at the 1.46 CC. It will not eject the round. I haven't gotten back to the range to shoot the increased 1.5 or 1.6 cc.
A little reading later indicates this power is great for lighter varmint loads like the 20 grain Remington Fireball. Lee Reloading suggests with VDM of LT-30 is .0750. VDM x start load powder grains suggested (19.4) for 55 grain bullet is 1.61 CC. The jacketed bullet should produce a velocity of 2860 fps.
Thoughts on why this is not ejecting the case? The standard 5.56 and .223 commercial rounds have never failed to eject. I double check the grain weight of every 5th round when dispensing using the lee perfect powder measure. Could it be as simple as to light a load??

 

[AJC1]

The powder is very fast and might not produce a lot of gas... lt32 is a little slower and was targeted at the bench rest crowd... most of those guys run n133. The gold standard of 223 ball powders in the 55 to 77 grain range is tac... as you go up in power I think your function issues should resolve. Go a little slower on the burn rate chart next go around

 

[Engineer1911]

Don't believe everything you read in the Lee loading manual.

 

[Hooda Thunkit]

Go a little slower on the burn rate chart next go around

Or a little lighter on bullet weight. That lt30 works better with 40-45 gr bullets.

Don't believe everything you read in the Lee loading manual.

Or any manual. Lee simply reprints data (with permission) from other manuals.

 

[Blue68f100]

Sounds like your a little light since it's not ejecting all and locking back on the last round. Since your at min bump it up a little and you should be fine. Just load a small quantity to test. Load a single round in the mag to test. This will tell you if you have enough energy to eject and lock the bolt back. If not, increase it a little more.

If you have an adjustable gas block, you may need to open it up some more. If by chance you have a way to change your buffer weight is another option.

Like said earlier the powder you have is not optimum for the bullet weight your using.

Do you have a set of scales to check your charge weight with? Most of the time the charts provided are not going to match with your powder. You need to build your own table with your lot of powder.

 

[N555]

I have loads like that. They will cycle a carbine but not a rifle length.

 

[rdnktrkr]

I second the suggestion to weigh your powder charge to see how close to minimum you are, I've found that the suggested CC charge in the Lee manual is below the charge weight but it is close

 

[FROGO207]

Yep sounds as though have a light load there. Yes you need to weigh your load and see what it is. When you get an accurate load you can modify your measure to drop that exact amount with a spare set of discs and a file. The advice about using TAC is spot on, if you can find any that is. I usually find two accuracy nodes when working up a load and also find the lower one is often the widest with respect to charge weights. Then I try to load using a weight in the middle of that node for maximum stability/ accuracy.

 

[GeoDudeFlorida]

VMD can fluctuate up to 10% lot-to-lot. This is why weight is the standard for smokeless powders, not volume.
You can calculate the VMD of your lot by using a precise 1CC volumetric measure - NOT a Lee dipper! Something precise like an Apothecary measure or Pharmacist measure - and divide volume by weight in grains. Use a lab grade scale to measure grains and repeat several times to verify the results.

 

[DaveH14]

Or a little lighter on bullet weight. That lt30 works better with 40-45 gr bullets.



Or any manual. Lee simply reprints data (with permission) from other manuals.

Thanks for the thought, I was leaning on the 40 Grain for the LT-30 and will try it for sure.

 

[DaveH14]

VMD can fluctuate up to 10% lot-to-lot. This is why weight is the standard for smokeless powders, not volume.
You can calculate the VMD of your lot by using a precise 1CC volumetric measure - NOT a Lee dipper! Something precise like an Apothecary measure or Pharmacist measure - and divide volume by weight in grains. Use a lab grade scale to measure grains and repeat several times to verify the results.

I did calculate the VMD by weight in grains as described in the book. I went out to the range and shot about 100 rounds and had multiple feed problems. These rounds were a bit longer than the bagged target rounds I purchased. Next time I'll make sure the length is right and the load is up gradually. I also have CCI 41 (magnum primers) only ones I can get right now. Lot of variables there.