IMR 4227 for supers and subs???

[GunFunZS]

I should have mentioned that I've switched to Winchester small rifle as my standard. They're just hard enough that I feel safer with them with the floating fire ring pin in AR-15s. However in the last couple of range trips I've had maybe four duds, Even with restrike. So I don't know. Standard CCI small rifle seem too soft for me to feel very safe. And the military version of them are both more expensive and not reliable in terms of finding them in stores. so I'm just inclined to standardize on something that I can't expect to find. Winchester small rifle seems like a nice compromise so I generally work up my loads around it unless there's a reason not to.

[Jesse Heywood]

I have only loaded sonic.
150 gr Sierra Game King, 4227 17.0 gr
125 gr Nosler Ballistic Tip, 4227 18.0 gr

[Rasha]

I started in on 4227 back in the early days of SAAMI adoption for .300blk because the "go-to" powders of A1680 and H110 disappeared pretty quick. I've loaded both supers (primarily 125gr) and subs (everything from 180-240gr) with it. It shines as a subsonic powder in that it's quiet and low-smoke and generally functions for supers even if it isn't ideal.

Some of my pet loads:
-203gr Palmetto Projectiles (now-defunct), converted LC brass, 10.5gr 4227, Tula KVB223 SR(M?) primers gave me right at 1000fps from a Faxon 8.5" barrel. Accuracy was poor but every load I tried with the PP 203's was bad and this was one of the least-bad. Still made a good plinker load. This load would not chamber in my 16" barrel (home-turned on a Green Mountain blank with a PT&G "match" reamer), has a short/tight throat that doesn't like cast subs). SD/ES aren't great with a heavy crimp but I was getting bullet setback with light or no crimp in an AR.
-217gr Gallant, converted LC brass, 10.0gr 4227, Tula KVB223 primers. Chrono's about 960fps from the 8.5" Faxon. Decent accuracy, roughly 2" 5-shot groups at 50yds. Will chamber and cycle unsuppressed in the 16" but is supersonic and has absymal accuracy (10+" 5-shot groups at 50yds). SD is okay, ES is good for cast loaded on a progressive press.
-245gr NOE (drops 239.something after PC with my alloy), Sig factory brass, 8.8gr 4227, Tula KVB223. Only about 880fps but gets full function unsuppressed in my Faxon barrel and full function suppressed in my 16" barrel. Accuracy has been good to excellent (1.8" 5-shots at 50yds in the Faxon, 1.5-1.7" 5-shots in the 16"). The near-100% case fill has led to low SD/ES and this bullet likes a heavy crimp.

The problem I run into with 4227 is with light weight supers. It just doesn't produce velocity like H110 or 300MP do, and I've been a little disappointed with its accuracy.

[Shaman]

My RARR shoots well with 18.3gr 4227 and 110 v-max. Sierra 125 gr (2120) with 18.7gr.also shoots well. Getting a smidge over 1moa.

[plant.one]

Standard CCI small rifle seem too soft for me to feel very safe.

if you want to do a test.... next time you're at the range, load up a cci 400 behind a load you know is safe.

chamber it 10 times from a full bolt drop with the release button or with the charging handle dropped when held fully back, while ensuring the barrel is pointed in a safe direction down range. it WILL dimple, but if it doesnt fire after 10 strikes... that has to install some level of confidence on sufficient cup thickness as well as cup hardness eh?


as a side note - its also a good test for neck tension to see if your bullet is moving during chambering, so bring your calipers to monitor COAL during the process. might as well take advantage of the opportunity to collect data.


i know my sample size is relatively small, but i've used CCI 400's as my standard blackout, 223 and 204 primer for a very long time now. ive fed 6 uppers, suppressed and unsuppressed, subs and supers, with them with various buffer weights in play (including my 450 bm with everything from a standard carbine buffer to a H2 buffer + 4oz lead slug in the bcg) and its been my goto primer for almost all my SR loads since i started reloading.

i'm comfortable saying ive burned thru >5 bricks of them by this point, and thats a conservative count.

never one slam fire. not even once. i'm also very comfortable that i'm not alone in this usage, or similar experience of their reliability by many many others out there.



I'm not suggesting that you're doing anything wrong with switching to WSR, but its also worth noting that they're only 0.001" thicker (an increase of 5%) than the cci 400 is - while the magnum primers and military style ones are coming in at +0.005" thicker (a 25% increase in thickness), at least according to the charts out there - im just giving a reference point to help keep some google searcher from hitting this thread thinking the cci's are likely to be problematic in an ar-style rifle platform



HTH

[GunFunZS]

I appreciate your input. I have done some of those tests but not quite that thoroughly. I suppose I was being subjective about it Just noticing that the dimple occurs on both but is significantly smaller on the WSR.

My thinking was partially that just because it is safe in my rifle does not mean it would be safe and somebody else's. For instance would it also be safe and my cousin's AK pistol. WSR just gives me a little bit more confidence in that aspect but presently unless confidence in reliability.

[GunFunZS]

I would appreciate input from people about whether it is a better idea to be using small rifle magnums for these loads too I've noticed that a lot of you do that.

[dellet]

That chart was done by James Calhoon back in the mid 90's. He was studying pressures and pierced primers in bolt actions. It had nothing to do with slam fires, but people apply it. The firing pin on most semi-autos is larger and more round than a lot of bolt guns

The basic take away is standard primers up to about 40,000 psi and magnum above that. That's part of the reason people see pressure signs long before max loading when they use the 400's and 6 1/2's in high pressure cartridges.

http://www.jamescalhoon.com/

A shortened reprint here
https://www.accurateshooter.com/technic ... -analysis/

I tend to have better luck with the magnum primers and double base ball powders like 296 and 1680

[TRshootem]

"I tend to have better luck with the magnum primers and double base ball powders like 296 and 1680"....Dellet

This is my experience as well, particularly with compressed supers loaded with 1680. H110/296 are used with SR-M's for best results. The CCI 450 is my favorite.

[ashman40]

For me, this load was surprisingly consistent with 110gr "black tips" thru my 8.5" pistol gas AR.
CCI 400 primer
110gr Barnes TAC-TX
COAL = 2.250"
17.7gr IMR 4227

My IMR 4227 plinking load:
CCI 400 primer
150gr FMJ-BT
11.0gr COAL = 2.055" (in cannelure)
16.0gr (COMPRESSED) COAL = 2.055" (in cannelure)
17.0gr COAL = 2.220"

As always, work your way up to these loads for safety sake. Note that one of the above loads is compressed.