Hi. I am new to reloading. Starting with 9mm. I picked up RMR brass plated round nose heads, and some CFE pistol powder. I followed the hodgson LRN data since I can't find RMR, min load is 4.9, max is 5.6, I settled on 5.2 since any inconsistency in powder measuring would still fall within that range.
I tried 20 rounds in a G17 with a Patmos arms upper (might be stock glock spring). Loads worked well as far as during and recoil. Loaded 200 more, checking powder consistency every 20 or so. Theirs 50 with the stick glock upper and it was a failure. Loads felt weak, and couldn't recoil. Other than the upper the only thing I changed was seating depth by about 0.010 inch. Could that difference in seating depth be that drastic? Has anyone tried to calculate figuring out the distance from the tail if the bullet to the end of the shell vs COL?

you might have to go up in powder.  should test various powder levels before deciding which one is best.  function and accuracy

plunk test is very good for determining COL for a specific gun/barrel
should hear a plunk when dropped into the barrel, and spin freely using your fingers.  if it binds it could be too long.  start with longest COL, then slowly go shorter, doing plunk test each time until you get it to plunk and spin 

you might have to go up in powder.  should test various powder levels before deciding which one is best.  function and accuracy

plunk test is very good for determining COL for a specific gun/barrel
should hear a plunk when dropped into the barrel, and spin freely using your fingers.  if it binds it could be too long.  start with longest COL, then slowly go shorter, doing plunk test each time until you get it to plunk and spin

Thank you for your advice. I've done the plunk test, (experimenting with a dummy round) and found the cartridge can be pretty long before it doesn't "plunk". In fact so far it struggles to chamber. I have a few rounds at different seating depths , to see the effect on pressure , and a few at higher powder levels to take to the range tomorrow. Thanks again

What grain weight and type (JHP, Plated, FN, RN etc...) boolit

What grain weight and type (JHP, Plated, FN, RN etc...) boolit

heads

Hi. I am new to reloading. Starting with 9mm. I picked up RMR brass plated round nose heads, and some CFE pistol powder. I followed the hodgson LRN data since I can't find RMR, min load is 4.9, max is 5.6, I settled on 5.2 since any inconsistency in powder measuring would still fall within that range.
I tried 20 rounds in a G17 with a Patmos arms upper (might be stock glock spring). Loads worked well as far as during and recoil. Loaded 200 more, checking powder consistency every 20 or so. Theirs 50 with the stick glock upper and it was a failure. Loads felt weak, and couldn't recoil. Other than the upper the only thing I changed was seating depth by about 0.010 inch. Could that difference in seating depth be that drastic? Has anyone tried to calculate figuring out the distance from the tail if the bullet to the end of the shell vs COL?

When shrinking your COAL by a hundreth of an inch it is best practice to drop your powder charge by at least a few tenths of a grain and recheck for high pressure indicators.

That being said, it's been my experience than shrinking your COAL is NOT a reliable way to increase slide cycling reliability (increase recoil). If your loads are feeling weak and barely flopping out of your ejection port or even stove piping, you need to either, 1) load hotter, or 2) lighten your recoil spring.

If you don't have a chronograph yet, it would be a worthwhile investment as it will give you hard metrics and make your reloading endeavors a lot easier to manage.

If this was my project, here is how I would play it....
A= 1.15 in.
B= 5.6 cfe
C= 0.375 in.
D= 115 plated round nose.

If this was my project, here is how I would play it....
A= 1.15 in.
B= 5.6 cfe
C= 0.375 in.
D= 115 plated round nose.

That's about my dimensions as well. But I'm using titegroup so that's different

I've found that my COL is very similar to what's listed in the lyman manual
I never go outside of recommended dimensions or powder weight
If I want stronger ammo  I'll switch powders to one that is made to shoot hotter
Take 44mag for instance. If I want hot, I'll go ACC#9 or H110. If I want not hot I'll go ACC#7 or trailboss or something designed for not hot ammo

Thank you all for your awesome information. The rounds I lowered to 1.10 worked well enough to use today.  The rounds I upped to 5.6 fr I'd CFE pistol worked consistently. I am using Ricky mountain reloading heads, so I can't find any loading data in them. I went with the hodgson recommendation of 4.9 minimum with LRN. I am using brass plated round nose , and have been told to go with the charge weights of the plated head.  That gave me 5.3 to 5.9 max.  I settled on 5.6, with 1.10 CO l and those worked well. 
Currently I don't have a chronograph, but am looking into one.  Tha k you again

Ill add on to the urgency and necessity of getting a chronograph as soon as you start reloading. Most dont because to get a decent one ala magnetospeed ish or labradar its quite an investment. But imo it increases the safety of what you are doing 10 fold.

Checking pressure ala ejection, brass markings, primer cratering, etc are great tools, but most are highly subjective. My degree of safety for primer cratering may be slightly different than you or your friends. One thing that is objective is muzzle velocity. Measure it on starting loads theoughout entire load development. If multiple manuals and forums report geting 1000fps for example for a given load, if your starting load development and are at 975, you best believe you better be careful when climbing that ladder. Another situation would be a new reloader who thinks hes at safe pressures because he doesnt have ejection issues etc , but in reality his mv could be upwarda of 1100 fps. Theres no secret fairy tale physics going on. If your achieving 100-200 fps more than others with the exact same load, the pressure needs to be escaping somewhere. Whether it may mean you are just sacrificjng brass life or potentially putting extra stress on high fatigue areas

. One common thing is with titanium bolt action rifles (i know this is a diff weapon system). But often they can disguise bolt lift issues with high pressure. But if your not carefully checking MV you can easily hit psi that is not intended for long term use and slowly peen back the lug abutments.

Sorry for long rant. Hope it makes sense ish. Always want people who are new to reloading to be safe and not visit me in the icu lol.