The article is solid, if somewhat rough. It needs more proofreading for grammatical reasons alone.
I don't know, if you have gotten proper feedback, but I would recommend to return to that stage of the writing process, to analyse the flaws which may exist besides some grammar.
There is no incentive for anyone to give feedback to "posted" articles like this, so don't take the silent downvoting personal. If it was in the sandbox and this was the forum for feedback, I would say you are at 90% completion.
edit: I am writing more complete criticism now. brb.
Special Containment Procedures: As of 08/19/2013, SCP-3387 has been reclassified clear of any anomalous properties and is stored to be stored at Washington Confederate Cemetery in Hagerstown, MD, where it's to be kept for long term storage. (neutralized remains of anomalies are usually incinerated, however in this case a reference to a reason, which does not even need to be written out, considering the context of the neutralization, would complete this line for me.)
SCP-3387 is to be kept in a standard sized containment cell with lead ventilation systems in place to clear out any lead particles in its cell.
One of the walls must be covered in steel plating to act as a backstop wall for SCP-3387. SCP-3387 is to be locked into a resting position, the barrel pointing toward the steel-plated backstop wall, with a tightened metal gun rack. Wire rope is to be wrapped around SCP-3387 and the gun rack for extra reinforcement. The gun rack is to be fastened onto a metal table using screws, and the table is to be fastened onto the floor using screws as well.
A Sound-capturing security camera is to be stationed in the containment cell. In the instance of SCP-3387-02 and SCP-3387-03, sound and video recording of the incident is to be downloaded onto all Level 2 researchers’ computers associated with SCP-3387 to be studied.
This whole section is a bit too specific. It is a gun, which fires occasionally. It is entirely sufficient to say, that it is affixed to the ground, and points at a durable and replacable target.
For cost reasons, the bullets may even be used in the manufacturing of this target, if the guidelines in your headcanon allow for that level of lax skip-handling.
After SCP-3387-03, Level 1 janitors are to be instructed to clean the cell of SCP-3387 to remove any trace of lead, pick up any bullet fragments, and to replace any damaged steel plates on the containment cell’s backstop wall.
SCP-3387 is an Enfield Pattern 1853 rifle-musket, with signs of use and wear but otherwise has the appearance of a normal rifle of this type.
Was there a check about the origin of it? Is is an actual rifle from the war?
SCP-3387 has three distinct stages, the first of which being SCP-3387-01, its default stage. While in SCP-3387-01, SCP-3387 is unable to fire Minié Ball bullets, and cannot be repaired in this stage, rendering it unusable. SCP-3387-01 usually lasts around a week before SCP-3387-02 starts, the second stage of SCP-3387
The stages would probably be designated states. Stages are for diseases or named processes, which this is not (but could be).
slowly getting louder
Not sciency enough for some. At a glance ok though.
with no need for the voice to catch its breath.
Replace that with the word "uninterrupted" somewhere in the previous sentence.
The Minié Ball bullets and powder SCP-3387 uses during SCP-3387-03 are created from within SCP-3387 itself during SCP-3387-03, which is confirmed by the fact that during SCP-3387-01 and SCP-3387-02 the barrel is empty. After SCP-3387-03 is over, SCP-3387-01 begins again, restarting the cycle.
A bit cumbersome. This basically says, that
The projectiles and powder used during stage 2 only come into existence during stage 3.
After the firing concludes, SCP-3387 returns to stage 1.
The way it is written now, the only condition for the skip to stop firing, is its eventual return to stage 1. This never happens, because the condition for that is the end of stage 3, which has no condition.
Think of these stages as a program, if that helps.
Every instance of SCP-3387-03
These are not instances, but occurrences, I think.
Addendum 3387-A: SCP-3387 was discovered by Foundation Personnel in the Museum of Southern History in ████████, SC on 04/26/2012.. The Foundation was alarmed when reports of an antique rifle screaming and shooting people from within its display was sent to local law enforcement. Upon arrival to the museum, 1 person had been shot, and the rest of those who were at the museum were sent to stay in one of the other rooms, where they were all administered Class-A amnestics. The exhibit SCP-3387 was placed in was the newest exhibit at the museum, and was labeled "The Haunted Rifle", with a plaque on the bottom of the exhibit. The plaque read as follows:
This is not a simple addendum, but a recovery report. There also is no mention of any investigation into the person, that introduced the skip to the museum, which is odd.
These messages have been documented since its introduction to Site-██ on 05/04/2012.
Addendum 3387-B: Log of Messages from SCP-3387-03 since its introduction to Site-██ in 05/04/2012
This is usually done with the first one referencing the existence of the second one.
For example: These messages have been documented in Addendum 3387-B.
Addendum 3387-C: On 07/18/2012, during testing with SCP-3387 during SCP-3387-02, it was discovered that, through pulling back the trigger of SCP-3387 in Morse Code, researchers would get a direct message back during SCP-3387-03. This could be repeated for several subsequent messages, culminating in an interview with SCP-3387.
- Collapse
Interviewed: SCP-3387
Interviewer: Researcher █████████
<Begin Log>
Researcher █████████: CAN YOU HEAR ME?
SCP-3387: YOU CAN HEAR ME?
Researcher █████████: YES
SCP-3387: WHAT TOOK YOU SO LONG?
This is an odd start to what seems to be the first accidental conversation. No mention of the odd firing or whatever happened during the first accidental message relayed.
I would recommend a solid [superfluous dialogue removed] or however it went.
Closing Statement: After the interview, SCP-3387 returned into SCP-3387-01. For the next month, SCP-3387 went into SCP-3387-03 each day, skipping SCP-3387-02. During SCP-3387-03, SCP-3387 transmitted the same message every day: “BURY ME WITH MY BODY, AND ILL BE FOREVER FREE”. Any attempts to communicate with SCP-3387 turned no results. After a month of this, the corpse of Jake ████████ was located in the Washington Confederate Cenetery, within Hagerstown, MD. Upon inspection, Jake ████████ showed no signs of decomposition. Whether this is due to the absence of SCP-3387 is unknown at this time. It was decided that SCP-3387 would be moved to Jake ████████‘s coffin, where it would be monitored by one security officer for any anomalous effects. After a year of no anomalous activity, Jake ████████ had already decomposed considerably. The security officer was removed from the cemetery, and SCP-3387 was reclassified as neutralized.
This is the closing statement to the interview. The neutralization is a separate matter.
This took longer than I thought it would. Please take it with a grain of salt, as the biggest contribution to the site on my part was a brainstorming session, which led to a space related skip by someone else. Not all of this is important. It just stuck out to me.